Cramping at 4-5 Weeks

Me
I have period cramps and I've had them for about a week (I'm 4 weeks, 6 days pregnant). How long can I expect to have these?
I had a miscarriage a few months ago and it was right around 5 weeks and felt those harsh pelvic cramps--that's not what this is. But every time I start cramping, I get so nervous and scared that this will happen again.