Has this happened to anyone else??

My daughter is almost 2 months old. For the first month or so, she was extremely fussy and inconsolable. After researching, I felt like it may be a milk allergy, so I asked to get her tested. We had to wait until the weekend was over, so in the meantime, I gave up dairy. She seemed to be doing better, but I had also started her on Gerber soothe probiotic, so I wasn’t sure which was causing the change. Well fast forward, we get the test done and it comes back negative, so I resume my normal eating habits. It seemed like we took 3 steps back! Our daughter’s symptoms came back and this lasted 3 days until I decided to give up dairy again. Well, she showed improvement again, but now I feel crazy! Has this happened to anyone else? I’m EBF, but I’ll be going back to work in a month and I wanted to buy some formula as a back up, but buying dairy free has me thinking I’m nuts! Lol I’ve also read withholding dairy unnecessarily may cause my daughter more harm than good. Any input or advice?