I’m not sure where you’re from so idk what type of heat it is but I’m in the Houston area so it’s been really bad here too. I’ve dealt with nausea since I was born basically. Typical nausea meds actually make me throw up- idk what med it is but it’s what my mom used to try and give me, it’s a liquid med. But the only thing that has ALWAYS helped my stomach is dramamine, and while I get motion sickness sometimes, I almost always am taking it when I’m just dealing with nausea, not caused by motion. It was a miracle pill for me really! I get a generic HEB kind and take 2 if I feel sick. As long as I don’t throw up within 15 or so minutes, I’m good. Every now and then I’ll have to take 2 more in 15-30 min bc it’s that bad. As for the heat, I’ve been in it everyday lately and I wasn’t for the past few years so I was feeling sick from it when summer started. Try and accumulate yourself to it. Just stay out for a little bit but a little long every day or so. Also, try to not drink anything sugary while you’re actually in the heat. Mainly just drink water. If you have Gatorade or something like that, a good rule is 2 bottles of water for every small Gatorade. You can actually way overdo it with sports drinks and hurt yourself instead of help. If your sweating heavily then definitely try to drink Gatorade, etc too though, it’ll replenish what you lose in sweat. Oh, and freeze a piece of fabric. You can get it wet or not, but it definitely helps cool you off!

Maybe get blood sugar levels checked...that's a sign of insulin issues

When we sweat in the summer heat, we expell salt and other electrolytes. Sounds like you're low on electrolytes- sodium, magnesium, potassium, and calcium. It is a common misconception that water will make you more hydrated. It makes the blood more watery but doesn't have the electrolytes to replenish and hydrate.

I'm constantly getting pain nausea. I used to take Zofran but Zofran caused my rare movement disorder which every treatment has failed so now they want me to get deep brain surgery. I also have problems with keeping on weight, chewing pain and very hard or nearly impossible with oramdibular dystonia. Thc, rso ect has been a lifesaver for me. Except sometimes I eat to much and suffer aftermath but worth it to me. I take breaks but then pain management ect start telling me to think about feeding tube and that's a no way for me. This is just my personal experience with alternative medicine

I never thought about doing alternatives I am willing to do anything to get my summer back for me and my daughter