5 months and still not feeling right?

I had a virus in December which lasted 24 hours or so, upset stomach and I fainted. Ever since then I haven't felt like I've got back to normal. I've have moments where I feel faint or my head just feels a bit hazy. I have a bit of ringing in my ears too, usually at night. I'm often really aware of my heartbeat, it's like I can feel it constantly and it also feels like it's skipping a beat at times. I wake up in the morning and always feel as though I haven't had enough sleep - I've never been a great sleeper and wake up for a couple of minutes around 3-4 times a night. I had a blood test in January and an ECG - both were fine. I had another blood test a couple of weeks ago which again was fine. I think my GP is at the stage where he doesn't know what else to do. I've had my eyes tested too, I'm slightly long-sighted but I'm not sure that it would make me feel like this. I'm constantly thinking about why I'm not feeling better and often wonder whether I'm making it worse by worrying about it. Whatever it is it's driving me mad! Advice would be really appreciated.