Sayang, I really can't say what it is from here, you need to see your doctor or go to the clinic ASAP, especially when you're pregnant, okay? I know it's scary, but better safe than sorry lah. At 7 weeks, your doctor should check you properly and make sure everything is okay with baby. A few of my mum friends always say the same thing, don't guess-guess, just go get it checked out. Take care of yourself, yeah?