HELP! Changed oil, clutch/transmission doesn't work!

I have a 1995 Mitsubishi RVR 4 clyander. I just changed the oil, putting 4 quarts of Castrol GTX 10W40 in, changing the filter as well. I just started it and the clutch/transmission is messed up. The car can barely get into gear. I hardly managed to pull it back into the driveway. Can oil level affect the transmission? This is mystifying.

The dip stick says there is too much oil... about an inch too high. I drained about 3.5 quarts out and added 4. But I just drained about 1 cup of oil out, restarted the engine for a bit, shut it off and rechecked the dip stick. The oil level seems unchanged.

Any quick advice would be greatly appreciated.

Thanks,
John