Originally Posted by Tom Pedale

Assuming that there is nothing physically amiss, what you describe may simply be the schedule your body is on. Are we talking about needing to go after every average meal or for example generally after lunch?

I once had a boss I could count on to hit the can every day after lunch. You could set your watch by it.
In lieu of posting this and the variety of advice you are going to receive, if you have concerns, professional medical advice is probably best.