My friend (who wish she had this app but can't cause of android) told me how she has not started her period in over 5 months since the last date. I'm a little concern for her cause I don't think that's healthy. She started being sexually active about a month or two ago so I don't think it's pregnancy and she uses protection. Should I tell her to see a doctor? She really is not concern about it but I'm a little scared for her.