Good fats are good for you! It's one of the resounding myths out there. People are so fat phobic.
I do agree that you are too young to have plaque build up. This has to be from something else.
Do you have medical insurance? I would go get some tests to see what you are dealing with, and go from there. It is putting stress on you trying to figure this out on your own. It is impossible for us to self diagnose. Once you know, then you can look for alternative means to improve your condition.