Unexpected period or spotting!

I really need some advice as i have no idea what the hell is happening. I got done with my periods on 25th march. On 26th or 27th  i had to take the morning after pill becz of unprotected sex. But on 7th april i noticed few brown spots and ignored. But on 8th and 9th i noticed bleeding and its not exactly menstrual bleeding but i do have cramps.  I have really sore and tender breats as well. And today morning i woke up with a heavy chest and irritable throat and cough. I searched online and i got to know these could be early signs of pregnancy but yesterday i did the stick test and the result was a negetive. Can somebody give me an advice as to whats going on?