I fell and hit my mouth and my implant is loose and I can pull it out. Can I leave it out until I see a dentist?

It seemed that you have already pull it out.  In that case, do not put it back in since there's a chance that you might swallow it.  Just leave it out and go see your dentist ASAP.
If you did not pull out the implant and it is still in your mouth.  I would then suggest that you leave it in and go see your dentist ASAP.

leave it out, my first question is only crown portion or root part also? visit your dentist as soon as possible. if root part is also out thn , u have to go for reimplant surgery followed by bone graft procedure. 

I believe that you should go see your dentist right away. It's very important that he knows what happened. So, that he can find a solution.