I don't think you just stop caring for someone.. and the thinking is natural but it does get better with time... then silly things can remind you, like a smell or colour and it feels like the world is crashing down again.
Talking, writing and expressing the bad and good moments helps the healing process.

Your T should be able to give you a few simple techniques to help with the thoughts, mine helped my learn to distract my mind when I was getting down by focusing on many things at once... it isn't a long term solution but good for the dark times.