I would go ahead and take a pregnancy test just to be sure. I know you don't want to know right now if you are pregnant but one things for sure at least you will know either way. Worrying about it everyday and night can be stressful, and sometimes that type of stress can cause your body to have a mind of it's own.
I have a 3 year old daughter and one that's almost 7 months....and honestly I think I may have liked them being closer together in age.
Because there does come a time, when you look foward to them being able to do some things for themselves....that can free up some of your time...and sleep.....oh my goodness....I would have rather not slept for a couple of years hahah...then to not have slept...got use to kind of getting a good nights sleep to not sleeping again....
My husband wants to try for a boy because we have two girls, and honestly if we do this, i'd rather start trying by the time my 7 month old is a little over a year old.
I hope you don't continue to worry.
Things do happen sometimes despite are efforts to control them. If you can get the courage do a test and if it's not positive you can laugh about it later.