lost all my progress

Whenever me and my freind tryna join eachother, it was always unable to connect. Each and everytime, i deleted mc hoping it would be fixed if i just reinstalled. I signed back into my one and only account, not rven my avitars was saved. My worlds were lost. Only the achievements stayed. Honeslty mc is falling off, this wasnt a problem on my end. Bugs needa b fixed.