Fussy eating sos

Please I’m really at a loss here. Waiting to see the ped on Thursday. For about 2 weeks now my LO has been a really unhappy eater. (Only during the day 🤔). Without fail she eats an ounce and then starts doing a mix of her hunger and tired cry but refuses the bottle. She’s exclusively fed breastmilk. It takes about 20-30 minutes to sooth her but last night she had an episode where it was on and off for 3 hours. Sometimes after she’s soothed she’ll finish her bottle or she’ll breastfeed. Some bottles she does perfectly fine, and others these episodes occur. I can’t find any correlation. I don’t know what to do I am at my wits end. My husband has completely given up trying and I can’t keep doing this for every feed I’m exhausted. Could it just be this 6-8 week growth spurt? Is it colic? Please help :( It’s absolutely not gas - she burps and farts/poos every feed. Soft belly. Different cry. We have tried mylicon and gripewater. Bottles: We were using Dr Browns L1 and bumped her to L2 thinking that was the issue but she was spitting up too much. We just switched over to Mam and she seems to latch to that bottle better but still having the same episodes.