Just turned 25 but convinced of my impending doom....

Hey everyone, I'm a bit new to this and although I've been through the forums and found it really good to find other people like me I was hoping to reach out and get some peoples thoughs/advice on what's worked for them! To give you some context it's 7:30pm here and I've left my loving bf in the next room with the excuse "I'm reading and need quiet" because I'm feeling anxious again and need to escape and be alone so I'm now in bed and have been researching health anxiety for the last hour. I used to be the most confident, outgoing and social girl, without a care in the world but since my first panic attack I've never been the same. An onlooker would probably think I have a pretty perfect life , loving bf, good job, nice house and good friends, but when I'm at home I'm completely crippled by health anxiety and it's literally ruining my life and I'm ashamed because I have so much I should be happy and greatfull for. The worst thing for me is it goes completely against everything I am, in the workplace I consider myself a conciencious, ambitious and tenacious individual but in my personal life I'm mentally weak and cannot handle my anxiety or rationalise my thoughts. I constantly monitor my body and a slight chest niggle is a heart attack, I had a 3 hour plane and I was convinced I had blot clots, I changed my pill recently and I'm constantly testing myself for the 2000 and 1 symptoms listed on the instructions which indicates pretty much everything means you should go to A&E, I've taken myself before and I used to go to the doctors all the time but I can't waste there time once again! I had my first panic attack 4 years ago and it became a daily occurance, my blood pressure was through the roof so I was put on beta blockers...at 21, I felt as though I couldn't get off the bed so I took them about 3 times then stopped! I quit my job at the time and although the panic attacks and high blood pressure stopped I have since then always been on high alert with my body. For the last few years I've thought it was under control and then the last few weeks it's returned with a vengeance and I just can't go through this again!! I see people my age care free and enjoying life and I just want to be like them, sorry to rant for so long but I would appreciate any techniques or anything that helps because I just want to escape my own mind at the moment xxx