Advice please!!!

I had unprotected sex may 16th (CD 14). On may 22nd and 23rd I spotted a little pink but only once each day when I wiped. The 22nd my breasts also became sore. I have had sore breast ever since. On may 24th and 25th I didn't spot at all that I saw. On the 26 I had brown spotting in the morning, only when I wiped. I still have brown spotting 6 days later! It's only gotten lighter as the days progressed. I'm concerned because I'm pretty regular with my cycle lasting 28-30 days. I've never had this happen before. I took a first response test this morning at one day late and it was a bfn. I'm planning on scheduling an appointment if af doesn't arrive in the next few days. I need advice from someone who has experienced these symptoms before? We're you pregnant or was it something else? Any input would be greatly appreciated. Thanks.