I Am Worried About My Health

Please help!. I have quite bad health anxiety, I've been getting calf pain, and pain behind my knee now since like a week. I have asthma and a cough has been present months and months now but I've convinced myself at the moment that the cough and chest tightness which is what I already get is a lung blood clot. I went to the doctor and they assured me it wasn't a blood clot, also went to a&e last night just in case. They checked my bloods, did a full blood count and a blood test to check for clotting, they wanted to do the canula needle but I didn't want the big needle. They did say that it was okay for me to have the other blood test for clotting and assured me it wouldn't affect the results. Everything came back normal so they did a chest xray which was also clear. They also measured my legs for swelling which was also fine. Blood pressure, EKG, stethoscope check also fine. They don't think it's a blood clot but I still have that fear in the back of my mind. Anybody gone through an experience like this?, I know this isn't a medical website but I feel that I get more support here.