Anxiety? Late Period and I am not sexually active?

I'm not sure if I have an anxiety disorder or his I am just overly stressed often. Since I was 8 I can remember having this fear of death. I never felt like I was dying or anything, but I have since had a hard time sleeping often because I am stressed by the thought of how unpredictable and short life seems and things like that. Am I just stressed or could it be anxiety? And how can that effect my period? It's been a month this week and no period, and I am not sexually active, but I'm panicing. My period can be regular but other times it can be irregular and it wouldn't be the first time its been late from stress and things, but I usually have symptoms the week befre and I haven't had any symptoms of a period or anything. It's making me stress even more! I haven't been sleeping well and I'm tired almost every day. What's going on?