What are some things to do to keep things off your mind and not stressed out and to keep postive?

I have a hard time staying postive because of what everyone says about me or me and my relationship, that I'm easy (only did it once wirh my long term boyfriend ) I'm the biggest bitch , my ex-boyfriend (we dated for 1 week) is saying i had sex with him , people try to separate me and my boyfriend and spreads lies about me or him and says he's wiped or I'm controlling. And I've had a hard year it's finally summer and all I do is over think everything. Also this school year I got really depressed and it wasn't good and sometimes I think badly of myself I try not to but it's hard.
What are some things to do to keep things off your mind and not stressed out and to keep postive?
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