Late period, extremely worried.

My last period was 48 days ago. I am not pregnant. The last time I had sex was less than a week ago, and we used protection (a condom). My last period was also late, but not this late. I'm very worried. I am currently taking Lithium and Lexipro, but I have been for a while (not sure if that would cause it). I do not know about changes in my weight (I do not have a scale and am not allowed to have one) but as far as I know I'm at a fairly normal weight. I had dark spotting and some blood for 5 days about 2 or 2 and a half weeks ago. Could that have been my period? It was light but still had blood (mostly dark dark brown). I'm very scared as a 16 year old. I've never been to a gyno and am worried about my moms reaction if I tell her something is wrong. Any help will be appreciated, thank you!