Overthinking

I'm always the anxious and overthinking type, observing every little detail, panicking over nothing, crying over everything. Not a fun type for me and anyone going through it with me, It seems like recently I've gotten worse with these sorts of attitude and overthinking and I can't seem to help myself with it.

I'm here to ask how people just calm down, stop the overthinking and just trust themselves and their partner that nothing will go wrong, I need some sort of guide, I don't want to hurt or controll my partner with my constant need of reassurance, comfort and all that. So please,,,

Any tips to make my brain shut up?