What to do if i'm 20, i rarely ever have periods and now i have anxiety (among other problems). help?

Stress management...: There are some simple stress management techniques that you can learn quickly, but i would also encourage you to get into psychotherapy & start talking about what is making you anxious. Depending on why U R not getting your period you should also see your primary care physician to make sure there is nothing wrong physically. Let me know if you need additional help.