1. Don't feel guilty. Easier said than done, I know.
2. Breast feeding is not for everyone. Didn't work for me. Tried EPing. Didn't work. I could produce enough milk. I'm a teacher I have a fabulous immune system...really wanted to give it to my daughter but I can't. She was born jaundiced and we had to supplement early to get her out of the hospital. My milk came in a week after her birth and she destroyed my nipples in the in between period bc she was so hungry and I wasn't making enough. I got so stressed that even once I went to a lactation consultant I could relax enough to breast feed. But using formula meant several things
1. My husband could help and I could get more sleep. More sleep=functioning adult=better mother.
2. I didn't have to get half naked all the time.
3. I could enjoy feeding times with my daughter and not curl my toes and distract myself to make it through the 15 minutes. I don't watch tv while we feed, I look at her, in her eyes, talk to her, and enjoy her company.
4. Others, like my in laws, can feed her so my husband and I can go out and be adults (aka go to Costco and buy diapers and formula)
so I guess what I'm saying is look on the bright side, find your positives and hold on. I really thought breast feeding was going to work and be wonderful and I wanted it for my daughter but it wasn't to be. Doesn't mean I won't try again with our second child but formula is what works best in my family. If you are going to school so you can get a better job so you can provide for your family, then you are doing the right thing. Formula is extremely close to breast milk, what you are missing are the antibodies from your immune system. Well, lets face it, kids are going to get sick, regardless. Getting further education will take you far and those benefits are nothing to put aside lightly.
You are doing what is right for your family and don't take crap from anyone and don't feel bad about it.
That's my $0.02.