Aptamil Pepti-Junior help

[u/SilverMarsupial7830]

i'm not sure if this post is allowed but i really need help and feel like i'm drowning. my 10 week old was admitted to hospital last week due to green mucus in her poo and constant spitting up every single feed and several vomits a few days prior to her admission and wasn't gaining enough weight. whilst admitted they found she also had a UTI which was treated for with antibiotics. they suspected she has a cows milk protein allergy and i had to stop breastfeeding and switch her to aptamil pepti-junior formula because i was already losing my supply and was wanting to slowly transition her to formula anyway so i didn't bother trialling a change in my diet.

at first she wouldn't take more than 50 mls but we've been adding in alcohol free vanilla extract to help with the taste and that's been helping a lot. she seemed to settle a bit better for the first few days but still wasn't really gaining weight. after a few days they discharged us to continue with the formula and antibiotics at home, she finished the antibiotics four days ago. my problem is that ever since starting the formula she seems to have these choking episodes where she has trouble either getting the formula out or back down and she becomes really distressed and scared until she's able to unblock the formula from her throat. she's still spitting up just as much and i mean a lot of spit up every feed. she's also been doing dark green poos (which i have read is normal) but they're more slimy in consistency and have such a strong odour that smells almost metallic or fishy. she seems more unsettled now and i just have a gut feeling something might not be right but i don't know if that's just my first time mum brain overthinking. i've been taking her temperature multiple times a day and she's always within 36.5-37 degrees so in the normal range. i know the antibiotics could have upset her stomach and that might be the reason why and i know it can take 1-2 weeks for her stomach to adjust to the new formula while the dairy leaves her system but i just can't shake the gut feeling

i'm booked into see her doctor in 2 days but i'm just looking for advice or anyone who may have experienced the same on this formula to help de-stress a very anxious mum please