Yes, it’s fine to take time off of IF to deal with illness. Or whatever.
The important thing is, when you’re ready, get back to your plan. Or a new plan if you need it.
The only thing not acceptable is giving up on your weight and goals, because you’re worth the healthier you.
Please don’t stress yourself more by worrying about IF. Get well feel better and get back to it. You will do fine. We are all human and it’s ok to take a step or two back once in a while. You taking 2 3 days off IF is not going to have a HUGE impact. Get back to it once you are well.
Have a good day