So when I'm driving in the rain, I notice drops coming down every few minutes from in between where my automatic shoulder belt slides up and down. It's towards the front of the door. What can i do to fix it w/o effing up the shoulder belt?

 

Check your sunroof. It could be seeping in through your roof. Also check the door weather trim.

 

I don't have a sun roof, i'll look for leaks in the whether stripping in between there, can I use gasket sealer to fix it?

 

Also look at the roof seam beneath the rubber roof molding. Leaks typically travel with gravity.