13 DAYS LATE

I'm so confused I had sex during my fertile week 6-12of Jan and apparently ovulated the 11th my period was due the 25th and it hasn't shown at all, when it was meant to start all I have was so so so much discharge like thickish white no smell, at 9dpo I got a bfn and I tested again the week my period was due on the Friday, got like a super faint line sort of indent and I'm too scared to test again, I don't know what's going on I've had so many symptoms I've lost count lately I've had so much cramps and gas pain as well, I'm not sure what to do now. I've only tested with first response so far, I'm only 18 but I've never missed a period before 
I've had clear watery discharge for the past few days, my nipples were so sore I couldn't touch them now they are sore but I can touch them, I went swimming and in my stomach all I could feel was pressure!! I'm also exhausted!! All test taken 10dpo & before were beg or indent and I'm too scared to test again... Please advice would be so helpful