Been to a doctor? It could be anything from depression to dehydration to nutrient deficiencies to lack of exercise to lack of good deep sleep to thyroid problems to, again, just about anything.
I work out every morning before I go to work and try to do at least 3-4 bottles of water or more a day, but I haven’t been to the doctor I don’t want to waste a medical bill if they say there is nothing wrong.
I think its happen to you because of work stress or health weakness. If you don't want to go to the doctor it's ok. But you should take care of self for a few days. Take proper diet and rest. If you still feel that there is nothing happen well with you, then you should definitely see a doctor. It can be a serious issue.