I would ask for help at the herbal supplement store--there are things you can take to increase milk supply (mother's milk tea, fennugreek i think are 2)but i don't know if it works after you stop producing milk. Also contact your local hospital about a breastfeeding support group--the instructor might know something that'll work. Good Luck--I really hope it works.
If yur supply is gone, im not sure there is much you can do. I would try consulting with a BF lactation specialist. BF can be such a challenge, I BF DD at night and if im off work i try to nurse during the day but my supply is supper low during the day but full during the night, bcuz your body makes supply according to demand. I supplement during day and now im going to start wening her from the breast and just strictly to formula. I hope there is something you can do. If there isnt dont be so hard on yurself, you did a good job, some breastmilk is better than no breastmilk. I didnt BF my son who is now 14 and he never had any medical problems, I BF DD and she has been getting colds left and right.
try reaching la leche league. they could probably put you in contact with someone who can help.Or see if your doctor can recommend a lactation consultant although it may not e covered by insurance.