I often get worried about serious disease like cancer, heart, etc when I get mild feelings in my body that I cant explain. Hypochondriac? How to stop?

Therapy? Have you yet tried any form of psychotherapy? Typically, the optimal combination of things to treat emotional issues such as anxiety/depression is medication (which, on your best day, is supposed to take the edge off symptoms) but the real gruntwork takes place in psychotherapist's consulting room.