I was in the same boat dude. It sucks.

Get it serviced and drop the 100 bucks to make sure its got fresh parts and fluid. NEVER HAVE IT FLUSHED. Take it to an actual transmission shop to have it done right. I never did this step so it may save you.

I had to drop 800 bucks on a used transmission I was so strapped at the time man, it happens and it all works out.