It is very hot and humid in Florida at this time of year and this in itself can exhaust you. Yes, you do need to drink plenty of water. I strongly suggest that you have a fasting glucose test done to rule out diabetes. Some of your symptoms point to that possibility. If you can't get into the doctor for exam at this time, you can have the blood test done at a walk-in clinic or the local hospital. I hope all will be well with you!