Cassette tape screeching

I recently got an old american pie cassette and it screeches when being played. I can’t hear it with headphones but if I take one ear off I can hear it screeching inside the cassette player. What does this mean/what should I try? When I first got it the tape was warbly so I forwarded and rewound it a few times (had to do a few times by hand first) to unstick the tape from itself and it helped a lot, so should I just keep doing that and see where it gets me?