Second guessing decisions

I find that I often second guess my decisions, or I vacillate between things.  Today I vacillated about going to the gym and finally decided to go which was a good decision.  I did not second guess it once I decided and took action.  I also had decided to work from home.  But I keep second guessing it.  What if my boss thinks I’m slacking off?  What if I miss an important discussion that happens?  I notice that this occurs a lot when I make a decision that feels contrary to what I think I “should” be doing.