I hate to overthinking so much

So hello Guys I am 20Years Old I have autism and my Problem is sometimes I am Overthinking so much over things that brings down and makes me feel very very bad even at Night it sucks I am thinking sometimes over so many things good and bad things but sometimes I can't stop my Head to Rest sometimes in April until July it was extremely Hard because a person from my Work has died and it was extremly Hard to except it but with Medicine and my Family and my Therapist we find a good way out of my Depression I am Happy about it but sometimes I think about bad things not Suicidal no never but I need a bit help and tips t not overthinking so much and live in the moment and not in the past
Thank you Guys❤️❤️❤️