Is this OCD or something else??

I get a lot of anxiety where something very small will trigger that "fight or flight" where you feel your blood run cold, and from there I cannot let whatever thought it was go. There will be lots of seeking assurance, etc. This is usually either health related either by disease or chemical/poison, or a perceived threat from another person. Is this paranoia?? It is getting worse and I am now also experiencing anxiety about anxiety, e.g. I am worried about buying food in the supermarket in case it's been poisoned or it has gone bad somehow, because I'm scared of triggering the fight or flight sensation and the spiral that follows.

I'm on sertraline but it doesn't do anything for anxiety and so far the only suggestion from doctors is more CBT which there is a waiting list for. I just don't know what else to do??

Forgot to say I do have the classic magical thinking stuff where "if I tap 3 times nothing bad will happen" but I've had that for as long as I remember, this spiralling anxiety is more recent years.