Obsessive Compulsive Disorder (OCD)

I've just had lunch with my work colleagues and it was so hard for me to just seat with them at the table, eat my lunch and have normal conversation. I was very anxious going to lunch as I knew the canteen will be packed and certain people I know make me anxious from the way they look at me or talk to me. I feel like they can tell how I'm feeling or they may even thinking stupid or crazy because I tend to be quite when I'm anxious as I can't manage a conversation and avoid being confronted with questions or even sometimes avoid meeting people in the hall or out on the smoking patio as I would have to speak to them. I don't always feel like this and can be very chatty and normally I always was and it would take me ages to finish my lunch but these days I'm the fastest as I kind of hurry up to get it over and done with, have a cigarette after and go back to my desk. Today I just feel kind of dizzy and unable to concentrate, I feel like I'm going to faint or go crazy. I know you've all heard this before or even experienced it and I just hope it's only anxiety and nothing else. When I get a relief from m anxiety I feel like being re born, suddenly I'd feel happy and enjoy those moments but while I'm anxious I also get scared and frustrated and snappy. I just had to vent this out and hope that I'll be ok in a few minutes.