Sometimes I can't stop thinking about whether I locked my front door or not so I check it 3 or 4 times every time I go out.
Oh no, I think you have OCD :(
What is OCD and what do I need to do for it?
It  is a mental disorder where people feel the need to check things repeatedly
It drives me crazy.  What can I do about it?
The cause is unknown so I think just take good care of yourself and have someone that loves you nearby always