I'm 23 and I live a peaceful life. Good family. I have a job that pays well. 

Only regular challenge I get is the one that I expect(learning new things, training etc..). But when harder things show up, even the ones that I know I can manage but with hardship, I get anxious about it.   
For example, 

I have to meet guy called X tomorrow. I have a problem with him. I know that when I talk to him, problem will be resolved. Despite that, day before I can't sleep. Heart rate goes up, going to bathroom frequently, don't want to eat... Standard anxiety. 

I'm not the bravest of all but I never got bullied, never ran away from a fight.. I didn't have tough childhood but it was not easy either. 

I mean, if somebody physically attacked me and after the fight, problem was resolved, I wouldn't worry about it. On the other hand, if I had a tough conversation with someone tomorrow or even worse - in couple of days, then I would be anxious. 

Here is one more thing that can be related to my problem. I have a bloated stomach for more than two years now. Have done a lot of tests and everything came back normal. Doctor says last test that is left is Gastroscopy and if the results will be normal, my problem may be connected to my nerves.   
Stomach bloating started somewhere around the time when I started my first job. It wasn't very stressful but it was very new to me and overthinking became a normal part of my day.

My question is, do I have a mental condition that needs medical attention? Also, have you tried meditation like mindfulness?