Anxiety attacs...

Hiya,
I have been getting these anxiety attacs the past few evenings and it's really horrible!! I remember it happening once when I was pregnant last time but not like this!
Has anyone else had this?
I have a horrible cold too at the mo and feel really clostrophobic when I can't breathe properly which might have something to do with it, plus it's always in the evening when it's dark!?!?!?Any advice on how to over come this would be really appreciated!!!
Thanks,
Faith.xxx