Thanks for the concern. I went to the doctor and described the symptoms and she checked me over. I also explained to her that I've recently given up drinking and that I'm stressing out about work/financial problems etc. She said that I'd had an anxiety attack (which is consistent with what I physically/emotionally felt during it).
I'm already on citalopram so she didn't prescribe me any SSRIs but she referred me to counselling and printed out some breathing exercises for me to do.
Also, I went to my first ever AA meeting on Friday so hopefully if I keep going to those and post on SR regularly, that will also help ease my mental stress and anxiety.