It sounds as if you have an over active imagination - which may not necessarily be a bad thing, if you channel it correctly. Have you tried keeping a journal and writing down your thoughts so that you can reflect on them later on if you have a tendency to forget?

You might have some mild intrusive thoughts going on, but remember I'm no medical expert and you do have a sense of awareness and can distinguish between thoughts that aren't quite right.

You could also have a bit of paranoia going on. You have no proof something is wrong. It could even be related to anxiety.

Again, remember this is my personal reflection.

It's not a medical diagnosis.

I hope you find the answers you seek.