moms health and BF

my health isnt so great. do you think i should still bf. ive had alot of stress in the last 2 years, so ive been sick alot. i should have taken better care of myself. our ababy is due in 4 1/2 months. any ideas of what i can do to improve my health and be a good source of nutricious breastmilk for my baby. although bf doesnt mean just breastmilk, i am worried that since i am already suffering healthwise, bf might make me feel worse. anyone good at the vitamin supplement thing and know what would bring me back to the top. what vitamins supplements are good for bf? thanks