I was wondering if I could follow a ruling that I doubt a lot. What happens if the ruling turns out to be false? Is my act of worship that is effected by the ruling void?

I also have wiswas and a hard time getting over some issues

As long as you are following the most learned you follow their ruling on practice precaution. Unless you are a scholar (mujtahid) who has researched the issue and reached a verdict of your own. Waswas is from satan, he is our. Enemy and we have to fight him.