I'm the first person to read up on symptoms of a thing and decide whether or not I have it, so I'm not saying that's necessarily a bad thing to do, but in this case I really think you should see a doctor about these symptoms you're having. It doesn't sound as though you have gastroparesis to me at all, but something is definitely going on. Gastroparesis does not cause problems you do have, such as problems with urination to my knowledge, and it doesn't cause insulin resistance like what you're describing. It usually does cause inability to eat for feeling full or nauseated, which are all symptoms you don't have. So - bearing in mind I'm not a doctor - to me, that doesn't seem like a good fit.
It could be nothing, or it could be serious, but better to risk seeing the doctor for what turns out to be nothing, than to risk NOT seeing the doctor for something that turns out to be serious! Please don't spend any more time trying to figure it out online and make an appointment instead!