Why do I feel so weak

So I haven't posted here for a long while. I thought I had battled thought the worst but I was wrong. Since finding out I was moving house about an hour from my girlfriend I've been bombarded with break up urges and unpleasant thoughts. I'm scared because since I'm on an antidepressant I feel very little anxiety so all of this feels so real; yet earlier when i thought of losing her it hurt me to my very core. Please can someone help me, the thoughts of breaking up have become so constant since I knew I was moving and I just want to feel normal again.