Struggling with newborn

Not sure if anyone has any advice or going through the same thing.

I have a 5 week old, the past few weeks she has gotten worse and worse. Shes very difficult to feed, when shes drinking the bottle she often cries, throws herself backwards, spits it out, chokes etc. Shes formula fed, on aptamil first. Shes then very unsettled after the feed and is now basically constantly crying and wriggling around in pain.

Shes not sleeping well either, she rarely sleeps for longer than an hour and will then be awake for hours and nothing i can do will settle her back to sleep. The only way she eventually sleeps is lying on her belly on my chest. She also breathes really loud, snores a lot and breathes through her mouth rather than nose, not sure if that means anything?

Doctor first suggested changing bottles as they said maybe shes drinking too fast. So I now use MAM bottles with the slowest teat. She latches onto these better than her old bottles, but hasnt helped her uncomfortableness.

Doctor has now said it is silent reflux and gave us infant gaviscon. Ive given it to her for 5 days but ive decided to stop as i think its actually made her worse. Shes even more unsettled and sleeping worse and its also making her constipated on top bI will speak to the doctor again on monday.

But I’m starting to get seriously sleep deprived and I cant cope with seeing her so distressed all the time, I’m losing my patience and getting so upset. I hate seeing her like this.

Could it be reflux like the doctor said? Or colic?

The doctor said not to change her formula, but I’m thinking of putting her on one of the thicker comfort ones? Or trying a non dairy one incase shes lactose intolerant? I use infacol sometimes which helps her a bit, she farts loads with that and it seems to help but not much.

Just need advice, its making me really not enjoy these first months and I feel so down and a terrible miserable mother and thats not how i want to be, i feel so guilty and feel like im doing everything wrong