I also get it if I wake. But it's usually about something real lurking in my head. And I also am nervous about booking travel. Not because of insurance, I have been in hospital overseas and my insurance company was great, but just because I think I might be ill, and I travel alone. The last 3 years has been something happening one thing after another, me or a family member or friend. And I've now got that what next feeling. I expect bad news constantly. Don't be put of travel, go somewhere you're confident in if you do become unwell and maybe a shorter trip. Travel does wonders for your outlook and confidence.