Need help!!!!!

So I'm 128 days late. My sister says it's normal but one of my friends says I should see a doc. I'm definitely not pregnant because I am 100% a virgin. I just seriously have had no period for the past 3 months. And I've had alot of discharge like I have to constantly wash underwear becuase by the end of the day its all on my underwear. Has anyone else gone through this. I just need some advice on what to do

For those of you who have had a missing period before how on earth did you get your period back on track!!!