3320 brakes

My 3320 is having a problem with the parking brake. Last time I was mowing, the parking brake light kept going on and seems like the tractor bogged down and struggled to drive. Once I reached down and jiggled the parking brake making sure it was fully released the light went off and the tractor drove fine. This kept happening and even when the parking light wasn't on the tractor felt that there was resistance when I hit the gas. I assumed that my parking brake needed adjustment. I looked up the brake adjustment in the owners manual. I took a close look at it today and tried the parking brake. The parking brake seemed to engage fine and release fine.
But when I depressed the pedal brakes the parking brake clicked up and locked on. I tried this several times and every time the the results were the same. I looked up how to adjust the pedal brakes and it appears that they are adjusted correctly. At this point I am not sure where to start. Does anyone have any ideas?

Thank You