Hi, Sun stroke or heat stroke can lead to excessive dehydration. As it is mild, not much to worry. As you have taken lots of fluids, you must be experiencing frequent urination. Look for the color of urine, if it is more clear, means you are looking at excess fluids coming out of the system. If it is dark yellow, you are looking at concentrated urine, which I dont think so is with you. This is usually seen in dehydration. As you have recently suffered from heat stroke, you need to take plenty of water, stay out of the sun, and avoid strenuous activity during hot weather. Also, avoid caffeinated beverages. Next time you feel sunstroke, move to a shade, take cool beverages preferably with salt and water. If you strongly suspect Urinary tract infection, you can get a urine microscopy done and particular look for increase in WBC count or bacteria. However, you can wait for burning micturation or fever. But if you are diabetic, get the urine microscopy test done. If you have any further queries, happy to help again.