My 3 month old has been EBF until last week when I returned to work, and has had no issues sleeping through the night. She did great with bottle feeding milk I pumped and froze, and got a little lazy feeding from me. By end of the week she would want another bottle after I'd fed her on my lunch break. My stash is almost gone already because I cannot pump enough to keep up with her hunger. We began cutting her bottles with regular formula 50/50. I BF the entire weekend, and she did great. Come Monday, she woke up once in the middle of the night to feed, and now I am feeding her the second time in the middle of the night. Is this just a prolonged growth spurt, sleep regression, or am I not producing enough milk for her to drink from the breast anymore? I feel so discouraged and frustrated with myself for having to supplement, and I'm not getting any sleep so the anger and disappointment in myself is just getting worse.