I really need to vent/talk to someone right now or else I think I might actually lose myself.

I suffer from SEVERE health anxiety (and have been for 2 years now). It all started when I noticed a rash on my thigh, researched it, and convinced myself I had leukaemia. So for a year and a half I was worried about that every. single. day. It got to the point where I wasn't leaving my room and staying in bed all day. So I decided that it was time to see the doctor. Went to my doctor and talked to him asking about dizziness I was experiencing at that time and he said it was all anxiety. He did give me a form for bloodwork to clear things out there too (hormone issue, any disease...). Went and got the bloodwork done, results were 100% normal. So now my fear of leukaemia was gone but a new one started (brain tumour). So, 2 days after my bloodtest, I had a massive panic and had to go to the ER because again I was convinced I had a brain tumour. Went to the ER, told the doctor about my fears. He checked my eyes, balance, memory, and asked about my bloodwork results. I told him they were all normal and he was 100% sure it was anxiety. Before I left the hospital I made sure to ask him that if I did have a brain tumour would it show on the bloodtest and he said yes, to which I believed for like 4 days. Online all says only MRI's can show it. SO for about 3-4 months I was okay, still feeling a bit of balance issues but nothing major. Fast forward to this year. About 3 weeks ago I went to my therapist (hadn't seen her in 2 months) and towards the end of the session I felt as if I was about to pass out but I didn't. When I got home I tried to convince myself that it was because I wasn't breathing right and was very nervous but nothing helped. So ever since then I've been thinking about that every second of every day. Im getting symptoms like off balance, feeling like my heart is stopping, tingling of the face, and crying very easily. SO again 2 days ago I went to the ER and again was told it was anxiety. So thats 3 doctors telling me it's anxiety, and yet I'm not convinced because I have not gotten an MRI. The doctor said I would have more severe symptoms than the ones I'm experiencing now. So yeah, I'm an absolute mess. Im going to a different therapist (one more intense) soon but I don't think I can live like this anymore. Ive fully convinced myself I'm going to die any second from an undiagnosed brain tumour. Im feeling EVERY LITTLE MOVEMENT in my body. I feel even something as little as a hair on my forehead like it's something massive.

I also noticed that I have to either shake my leg, move my arms, or do something so that I don't sit still and feel whatever I feel.
I really need some help, anything would help. Anything. Thank you everyone.