two weeks ago mild vibrations out of the rear while in reverse like the limited slip was locked and the wheels didnt want to spin seperatly like i had posi or something

a week ago loud clank and clack coming from rearend not just sounds but hard shakes started happening in forward too now its everytime i take a turn always felt like it was the rear end, mostly happens on left turns in oppose to right

today got gas put her in reverse then forward started driving away and as my speed incrased this squeel came out of the rear end becomes louder everytime i slowed down for a red light.

basically i feel like my rear end is about to go and i have never had rear end problems and dont know what to do. i jacked up the rear today and took off both tires and spun it and it sounds like something may be broken/loose inside the rear end and when spining with my hand it would start to freeze/stop freely spinning and i would have to push hard and spin it in reverse than forward again to get it moving, which is what i bvelive is when i feel the car clank and clacking

what should i do?? my normal shop is closed on mondays of course but i have no idea what to expect damage or cost wise only that a few friends said i am probably best off going and getting a used rear end but i dont know how much it will cost to get it put on please help