12 weeks 4 days bleeding

Okay so I'm pregnant with my second baby. I had my daughter in May of last year, and now I'm 12 weeks 4 days with my 2nd little baby. I only ever had headaches with Isabelle. But with this one I've started bleeding a little bit today. Everytime I wipe it's there. Not alot. But there. And I've had some light cramps. I called my OB and they said drink water and stay off my feet as much as possible. But its freaking me out! I go Tuesday for my first Ultrasound, but I just wanna know if this has happened to yall. I haven't had but one cramp since this morning, and it happened right after I peed like 5 minutes ago. Can yall help? Thanks