Miscarraige at 11 weeks ?

Im 18 yrs old. Im currently supposed to be 12 weeks as of today. This is my first pregnancy. My mom calls me a hypochondriac but sometimes I think there is seriously something wrong with this pregnancy. Around 6 weeks I started spotting. I went to the hospital and the doctor did an ultra sound and the baby was fine. I went to my first doctors appointment at 9 weeks. I heard the heartbeat and he said I was having a healthy pregnancy. I dont see him again till im 13 weeks. Im really scared right now because I used to always have these growing pains that felt like minor cramps. I dont really have them anymore. The other day I got really sick. I had a bad headache, my temperature reached 99.9, my chest hurt, I was coughing up flem, and I kept feeling dizzy like I was going to faint when I stood up. My mom said it was probably something just going around because she had felt the same way 2 weeks before and my dad was sick too. I didnt bleed at all, but i had really bad pains in my stomach that felt like a charlie horse when I was out with my friends. It only lasted till i laid down. I just got over my sickness after 4 days. My stomach still feels uncomfortable and I have trouble sleeping at night because I have to lay a certain way so my stomach dont hurt. It isn't major pains anymore. Just little sharp pains every now and then. I called my ob/gyn on his exchange and told him everything. He told me it didnt seem like anything major and that I was fine and to come see him at our next scheduled appointment, and that if anything changed to let him know. Im just scared because I really want this baby. Can you please help??