Ugh baby allergies🤦🏻‍♀️ please help

My baby is allergic to something. At first the dr thought it was milk protein/lactose so I had to give up breastfeeding after 8 weeks bc she wasn’t gaining any weight. Went to formula and she started having blood in her stool, skin rashes, bad stomach pains, etc. so we switched to Similac Alimentum last week. I feel like she’s gotten worse? She has HORRIBLE stomach aches, like yelps and screams and cant even pass gas. Green mucus poops, skin rashes, can’t sleep, wheezing, and even choking on the bottle now. Before she was taking 5-6 oz every 3 hours now I’m lucky if we get to 3-4 oz. she’ll be near the middle of the bottle and choke everytime she eats and cant finish it. I’m trying the Gerber HA formula tonight and calling the dr tomorrow for an allergy test or something. I feel like this just isn’t normal. Anyone else have some experience?? Please share!!😭😰