Poor you. I can really relate to this, having suffered from chronic worry and anxiety for most of my life. Among other things, my health has always been an obsession.
I read a really good book about worry (I forget what it's called) in which the author defined worry as the intolerance of uncertainty. Worriers cannot bear anything but total certainty, but as total certainty is impossible the worry is endless. The moment someone with health anxiety is reassured by a doctor, they'll immediately start worrying about something else. And on and on.
And he or she said that the trick is to accept uncertainty. To accept that you do not have total control of things and be at peace with the. If you think about it, uncertainty about the future is not bad. It just means you don't know what's going to happen. It's neutral.
That really helped me - just accepting that I'm not that important in the grand scheme of things, and that I can never control everything and know everything right now.
There are also more everyday things you can do. You mention that you get lots of exercise, which helped me too. Also, if you haven't already, I'd recommend cutting right down on caffeine, or even cutting it out completely.
I don't know how old your daughter is, but if she's older maybe you could talk to her about your anxiety? If you feel that you have to hide your anxiety from her it could make it worse.
I've tried medication and I wouldn't recommend it. Everything they put me on made me feel worse. CBT can help if you've got a good counsellor.
Anxiety stems from a feeling of powerlessness, and that the world is a perilous place. Losing your father might have contributed to that feeling of vulnerability and helplessness. My mother left me when I was young and I felt like that too. Just understanding the root of your anxiety can help in itself.
I really hope you feel better soon.