A lot of people experience hallucinations right before sleep, or right afterward - has something to do with the state your brain is in, or something. Talk to your doctor about it, but don't panic.

What medications are you on (if any)? Some of them can have this type of effect.

Just don't freak out too much... it's not that uncommon. If you find they are persistent, effecting parts of your life seriously, or causing you to do things you don't want to do, go to the hospital.