Bleeding Oh NO!

I woke up this morning to go pee...and then went back to sleep to wake up about 15 minutes later with this wet feeling. I got up to check in the bathroom and there was bright red blood... It looked as if I started my period. Scary. I showed Tina and asked her to call our obgyn. My bleeding didn't stop right away, which frightened me, but our doctor said that we shouldn't worry. That its probably just Placenta Previa which means the placenta could be riding low rubbing on my cervix and annoying it. Also the uterus is stretching. My obgyn said just watch out for clotting and cramping. She thinks that after having that Nuchal Translucency Test and everything looking good..that everything should be fine, unless i lifted something too heavy, which I haven't done.
We had breakfast shortly after my bleeding stopped and I waited on the couch while Tina brought me my egg sandwich and all of a sudden I felt another gush..and ran to the bathroom to bleed more. The bleeding stopped again and I finished my breakfast and now I'm in bed..laying low. I called my sister and my mom and they were all panicked, which doesn't help my emotions any. My moms friend who is an obgyn is coming over to my mom's today for piano lessons with her kids and my mom will ask her questions. My sister thinks I shouldn't leave my bed all weekend. My cousin Katie's birthday is tomorrow at 3pm and it would mean the world to her if I was there. My obgyn didn't say stay in bed ALL weekend. My sister got mad at me for even considering going to Katie's party. Poor Katie. She's got cerebral palsy and doesn't have many friends. She's been looking forward to this for weeks. We'll see what my mom's friend says, but I think my sister is over reacting now. If the bleeding stops today, I should be fine to come sit on the couch by Katie. I can still lie low. Today we are 13 Weeks pregnant. The baby is supposed to be the size of a medium shrimp. This whole bleeding things is weird. Last time I had a migraine I spotted too. I missed school Tuesday for that ultrasound test and after that I got the migraine, so I didn't go to school Wednesday either. It finally went away Thursday around noon. I took a lot of Extra Strength Tylenol, actually a little more than recommended, but I didn't think Tylenol could hurt the baby. Scary.
My mom just called me and her friend said when a doctor says lie low..that means stay in bed with your feet up for 36 hours. She said i have to let it heal, that I could miscarriage at any time. Just GREAT!
I can't get over with all the tests I did prior to this...my uterus looked good. No scarring from the D&C. Plus, everyone says I should be exercising, but I've been waiting until my body wants to. I haven't had any energy, so I've been thinking, well this is just early pregnancy precaution. I better stop bleeding and never bleed again.
UPDATE: I stopped bleeding. Thank God. I took a shower around 5pm and then Tina made dinner and we hung out and watched tv. Thank god I stopped bleeding. Tina has been the hero today taking care of me as usual. Tomorrow we will take new tummy pics and add the shrimp picture (size of baby).