You did a great job to give your baby milk for four months under difficult circumstances. You can be proud of that. Your story sounds familiar to me, as well. I think the fact I was so sick combined with my baby being in the NICU definitely impacted my supply. She came home with a wicked flow preference/nipple confusion, and it took six weeks to teach her to nurse. I had a marginal supply, although if I knew then what I know now, it would have been better.
After that baby, I needed breast surgery that damaged my glands. I had even less of a supply for my next baby because of that, but we found a way to make it work even without a full supply. I would have had a full supply for one with my twins, but of course it was split between the two of them. I found a great support group at lowmilksupply.org and its sister site bfar.org.
Wife to Brett 6/30/02
Mom to Ethne Joy 10/12/03, 35 weeks, severe PE
Mom to Catie Grace 12/8/06, 37 weeks, mild PE
Mom to Riley Faith and Gavin Arthur 7/7/09, 36 weeks, PIH 22 weeks, PE 31 weeks, severe post partum PE
Mom to two angels 12/05 and 7/08
Running a Marathon for the PF: http://www.whatyourunningfor.blogspot.com