Feeling down.... a bit baffled.....

So it's been 3 months since I broke up with narc. Had NC apart from an email he sent me a month ago which I didn't reply to. Ive been doing really well, feeling positive, and even looking into Internet dating but the last 3/4 days I can't get him out of my head, I have feelings of missing him!! I feel really down & upset and I'm baffled and don't understand why after all this time I should be feeling like I do.

Anyone else felt like this?