Guys I'm so scared.

Every day I experience day dreaming. It's gotten to the point where sometimes someone will be talking to me and I won't realise until after. 

On top of that, there's a lot of pressure in my head and it's building everyday. I feel foggy and I can't think straight. I could go to bed in the middle of the day.

I'm on 10mg citalopram (celexa in US?) and have been for some time. I don't know if this makes it worse. 

I feel like it's going to get to the point I can't focus on anything at all or my head will explode or shut down.

Please help me. How do I make my head clearer?