Residual Symptoms?

I had the stomach flu about 3 weeks ago, and 2 weeks later, its still hard to eat solid foods in the morning because i might gag so I eat bland and sometimes this goes to lunch or dinner depending on what I eat. I feel constipated and i get slight stomach cramps sometimes but that maybe because I'm sitting a lot, which is why I starting walking after meals. I also feel tired sometimes throughout the day, is my  body still healing or is it the case of something more serious?

It's time for a medical check-up.

Id say go to the doctor. Are you strictly constipated? Any diarrhea? Are you running fever? 

Could be residual flu symptoms.  Wait a week ans if no better after this, see your doctor.