Positive OPK?

Kayla • Married & we had our perfect baby boy on 03/21/2015, Pierce Huntlee. He was 7lbs 10oz, & 19.5 in 💙
​I am CD 17. I have been using opks since CD9 and have been receiving negatives until now! I think I am very close! Glow estimated my fertile week the 3rd-9th.BUT I got this this morning!  I will take another about 2-3 to make sure I don't miss the surge! This is my first month ttc after removing my nuvaring on Janurary 13. Followed by my regular period from the 17-21. Let me know what y'all think? 
​Also on the 28-30, and this morning I am having light, brown rusty color discharge. Not sure why, no cramps or anything. Not pink or red either. Maybe my bc getting out of my system? Do you think I could still have a chance of getting pregnant with that going on? Feedback please!