idk what to do

idk why lately but ive been worried about every single little thing. nothing even really has to happen or go down for me to worry and work myself up over things that may not even happen. im always scared my boyfriend will cheat even though he has done nothing wrong and is always showing me unconditional love. im always scared my friends will turn their back on me when ive done nothing to them, and the list goes on. it gets to the point where it gets in the way of my sleep and even appetite. does anyone have any advice on how i could calm myself down some?