Grieving process. When is it too long and maybe a mental issue?

I was answering a question and as I answered this incredible sadness washed over me and I haven’t been able to stop crying. I had to leave my SO. There really was no choice, he’s so far gone with the drugs that he’s now homeless. I guess he was never who he represented himself to be. The man I loved and miss is a figment, or maybe it’s who he could have been, had he not been so messed up himself. So, I loved an illusion. Fine. I left and carried on smartly. So how ridiculous is it for me to miss something that I know wasn’t real? Am I ok grieving, or am I a nut who needs psych meds of my own? It’s been almost six months. Shouldn’t I be over it?