I got it in Mexico many years ago. Got sick 3 days after returning from the trip and stayed that way for 10 days. It ran it's course and symptoms declined over a month. Had I gone to the doc and taken medication, it would have been gone in 3-5 days.
So, yes, go get checked out and take the meds. I've heard of cases lasting much longer and recurring. I remember being dog sick and staying hydrated was a chore.