please help! have you had this happen???

Lauren
I will be 5 weeks tomorrow and today I have had very dull cramping (it doesn't hurt just an uncomfortable feeling hard to explain) in my Lower abdomen. I went to the bathroom (#2 - sorry TMI) and when I wiped there was some red blood there. I called my OBGYN who said if the bleeding increases to go to the ER. 
I have peed twice since then and the only thing was the first time I peed when I wiped there was very light brown almost not noticeable. 
Has anyone had this before? This is my first pregnancy and my husband and I have been ttc for 2.5 years so I'm worried about losing it.