NEED ADVISE PLEASE

I'm 18 days late for my period. My bf and I had unprotected sex using withdraw method during my fertile week. About a week later I got really weird spotting/discharge. It was bloody/brown and it was very light so I know it wasn't a period and it ended after a couple days. After some reading I thought maybe it was implantation spotting
I've been experiencing fatigue, frequent urination, nausea without vomiting, and mood swings. Im taking a test on Saturday but I just want someone who knows to share their opinion with me so 
Women who have had children, does this sound like what you experienced when you were pregnant?