Citalopram losing effectiveness...what's my next step?

Ok I've been on Citalopram now for about 2-3 months, one 20mg tablet a day. I had a month or so where it really started to kick in - I didn't have my usual mood swings and was in a good mood almost every day, and I found it easier to talk/interact with other people. Generally things were looking up. However, almost over night, the meds lost their effectiveness and I've pretty much gone back to my old self :sad: What should I do next? I'm not too keen on increasing the dosage becasue say that then loses it's effectiveness - where does it end? Should I switch to another med? Or just go see my doc and see what he says?

Do you trust your doctor?
mine wants me dead.

Citalapram makes you worse, its made me more ****ed up than ever before