how do i stop overthinking?

hi.. im 17 about to be 18 and i have been overthinking since i was a little girl. i was always left alone without being told anything and i was left alone when i was about 2 and i remember someone giving me oral. ive been scared about going out because of an issue with my dads friend and my brother touching me. also countless times that i would call my parents and they would never pick up i would always think something horrible happened to them and would cry my eyes out until they picked up. it's affecting my relationship with my boyfriend because i overthink about everything.. he forgot his phone in his car before work and he didnt text me at all on his break and i thought something happened. and i keep thinking he does things behind my back and stuff. i just need to know how to stop this. its so hard trying to stop myself. i have been trying and it works but after i jist get so sad. i am diagnosed with a mood disorder, depression, and anxiety. but i just want to get rid of this. does anyone have tips? i really love my boyfriend and i HATE doing this to him but i just cant help it because its a bad habit of mine.