45 days since last period

Amelia
Need help! 
Its been 45 days since last period I keep getting cramps but nothing turns up. I get bloated as well. Yesterday I was spotting a few spots of very light brown colour. But stopped. I did have sex a few times during my possible ovulation week and I took a preg test last week and was negative. This was taken late in the afternoon. Not sure if it makes much difference.I have been reading early preg symptoms and I don't have sore boobs or see any changes. I don't know what it could be? I'm getting really worried. Any info would really help