Need some advice or opinions

Okay I don't know if I'm at the right section but I really need some advice or opinions on this matter Several years ago 5 1/2 to be exact. I found out I was pregnant. I was in high school but I was an adult I was a senior. I was with my boyfriend at the time (now fianc) for two years. We had a lot of relationship problems during that time. Struggling to see each other ( not sexually) his family didn't like me at all (I'm older than him and they didn't want him to get serious to be exact they wanted him to be a playboy and try as much fishes in the see,they blame me for him failing class even tho he did it on his own I did his homework and such I was the nerdy one lol) anyways during the pregnancy it was hell literally. I didn't want to hide it we were trying to figure out how to tell our parents and how to provide for the baby etc... But with support from my family and his mother ( at time she was really nice and all and help us with appointments and such.) we made it good. The night I gave birth his grandmother (legally mother he adopted) told him he cant go to the hospital at all. But he went as far as sneaking out the house and hick hiking there. N so I gave birth to a handsome boy. After that when I thought things can't get any worse I was so wrong. His grandmother forbidden him to come to my house to help me with our son. ( I was a single parent) during those 5 months I was taking care of my son,going to school to graduate, and doing part time for college. Between those time I ended up getting a eating disorder and lost a lot of weight had faint spells everyday. Yes I stilled saw my bf but he was so depress that he can't be there for me n the baby. ( did I mention he was a minor at the time I was the adult) I hated him for it and it made me feel like he choose his grandmother over our family. During the time his mother was asking us about our options like who going to drop out n work while the other finish school. What are our plans. I told her no one dropping out and if it takes I'll work too and do all the things I'm doing. She offer us legal guardian while we are in school n getting on our feet. I didn't want to do it at all ( how I'm raise adoption or guardian is taboo) but the more I worked hard on everything the more I realize that my bf was hurting cause he was watching me suffer through everything (family,finance,school u know).in a way he tried to talk to be about giving his mother guardianship over our son. I said hell no but he made some points that it's better he be with someone who is more finance than us and we will work hard to get him back. In the end I started thinking and I thought maybe it would be best for my son ( oh boy was I wrong) so to be the first to do something no did in my family I changed my mind. But only under the condition that I get my son every weekend and holiday or whenever I want.(I should of gotten that in writing) we sign like some papers I only remember two. We sign one with a lawyer I don't remember really but we also sign one with her friend that can notify papers that one I clearly remember because I had a feeling something not right. That paper said something about me giving my parental rights up. I was skeptical about signing it that time cause of only I didn't really understand it but just had a feeling not to. But watching my bf sign it like it was nothing I thought he must of know what he doing cause he went through it. Well anyways after signing that a week later his mother came to pick up my son to live with her. (yes I was an idiot) and after that i realize I have to do something with my life so I jump my grades to average to above average graduated on time and went to college all within a year. I had my boy everyweekend and at some weekends my bf was able to sneak to my house to help me( my son is born in feb his dad became 18 in march) during the summer tho my bf went off to basic training and during that 3 months of training I never once had my son. I called I visit did everything. On forth of July that time I called n his mom said my son was sick but my older sister went to the mall with her family and saw her there with my son and he was perfectly healthy she ignore my sister. After all that things changed I only now get to see my son often when one she needs me to watch him or my fianc tells her to let me watch him ( she relunted to make me see him) or when my fianc驩 gets him he takes him to see me. For the pass years I don't get my son at all during the times he goes to training. And yes I tried. He attended school and he does have some behavior problems as well some other issue and his teacher wanted to know my son background but she can't find any paper at all about guardianship. Is there any chance at all for me to get my son back??? She not raising him right at all. My son is 5 years old he not potty train at all ,he doesn't eat healthy (all he eats is bread,pizza,hot dog with or without the bum) he not speaking clear at all for his age. She usually leave him in the room alone watching tv all day. And I think she a hoarder cause her house well if you Watch hoarders it's getting to that point! And second of all I have a feeling for years that what I really sign was adoption not guardianship. But I'm not sure cause we never went to court or see a judge or anything like that but she changed his last name I know that. Any advice or opinions would be very helpful?? And mind you this all happen 5 years ago