Health anxiety

Ok so, I’m not the best at explaining how I feel or what goes on in my head but for the past couple months I’ve had really bad health anxiety, like i always think somethings wrong with me or I’m gonna get seriously ill soon or the worst possible thing will happen to me. For example, when I have a headache I think I have a brain tumour or something and I over think and can’t sleep and then take panic attacks when I feel a bit of pain. I know it’s probs mostly in my head but when I tell myself that I just think but what if this times serious? Also, when I try go to bed I end up wakening up a few times during the night with knots in my stomach and my heart beating so fast and just feeling so worried. It’s the worst and it’s really affecting me. I went to the doctor but there just no help at all really:( can someone please tell me if they suffer the same or what I can do to help myself?