Hi! I'm really sorry to hear you're feeling this way. If you don't have any symptoms, or see any bugs, there's no reason to take tablets - many of those will have side effects and they're not intended for long-term use.
NB I'm no psychiatrist but this sounds very much like OCD symptoms - the fact that you feel really anxious about this and have to do these things in order to feel safe. It might be useful to look up OCD and see if it strikes you the same way. Ultimately it would be really productive for you to speak with your GP about this and they'll very likely be able to help - you're far from the only one with these kinds of symptoms.
Hang in there, this will get easier!