Is it acute hiv? something burn in my stomach every morning at 3am and 7am. sometimes i got diarrhea in low temperature?

I wouldn't think of acute hiv as causing your symptoms. Burning of the stomach can be caused by hyperacidity and esophageal reflux could also occur in the early morning hours. Avoid alcohol,caffeine, nicotine,spicy&oily foods. Take a medication like omeprazole or famotidine for a week or two. If not improved, see your physician or a gastroenterologist for evaluation, testing and treatment advice.

While your symptoms are not typical of HIV, the fact that you bring up a possible infection has to do with possible exposure in your recent past and for that reason HIV infection cannot be ruled out either. Seeking medical attention in these circumstances would be advisable as lacking sleep may affect your daily activities.