Mild pressure almost all day.

Background:

I am an 18 year old student who attends high school everyday. I eat very healthy (except for lunch at school), and exercize every day or two. I have always been pretty positive , however a couple months ago I formed a bad habit of worrying about small things that I should not worry about.

The Problem:

Throughout the day i'll notice that I have a minor amount of pressure in my head, especially when engaging in conversation. I can still act normal, and keep a conversation going, however the pressure is more severe (especially forehead), when in a conversation. When walking down the hallway I also feel this pressure, it is not as bad though. Sometimes the pressure if very mild, and other days it seems its a bit more strong, and when I notice that it is strong for a period of times ( an hour or two) then I will start to get a mild headache.

Any advice?