feeling completely overwhelmed

hi i have posted a few topics before and never had an answer for them so i hope sum1 has sum answers for me frm this basically i have been diagnosed with an anxiety disorder for a while now....my anxiety is totally hypochondria based..its ruining my life iv never felt so low frm it as i do now i have periods were im ok then out ov the blue something happens like i was convinced i had a heart condition was having palpitations chest pains all kinds countless ecgs an at least 6 docs tell me i was fine then i fort i had sum kind brain problem like a tumour or a anyerusm i then started to get pressure in my head head aches shooting pains all kinds once again then i sorta got over it bt every little thing i obsess powerfully over i mean like i reaserch diseases on the internet look up symptoms if i bang my head or run down the stairs or nething im totally paranoid im terrified ov dying its constantly in my mind i always think if i have a minor cold it could kill me one ov my new things is i wont wear tight socks in case they give me a blood clot!! an i have an abscess on my gum which all nite i have been looking up on the internet an now i can see it can occasionally cause death an now i cnt stop panicking an crying an feeling pains in my head an behind my eyes...so many times i have been to docters an a&e they must all think im mad or that i want to be ill i always feel asif i am illan i dont want to feel like this everyday is something new an i get so scared im dying. An to top it all off im 26 weeks pregnant an pregnancy has made this anxiety buisness a whole lot worse now i always think i have pre eclampsia or sum underlying heart condition is going to get me..i know i must siound so stupid bt i really cant begin to explain how debillitating it is i never say to people see you tomorrow cos i feel in my head thats tempting fate ..can anyone help me please