You ever felt lonely?

So long story short i realized I got a lot if things within I need to work on... my bf/bd & I always fought. Mostly because I started it either because I’d think about the past & would get so angry & hurt by it & would take that anger out on him. Well he ended up leaving yesterday & I just feel a bit lonely & sad.. I’m not sure what I should do or how I should work on myself & heal? Need advice 😞