Forgive me for saying this - but your question sounds quite ignorant and selfish.
Not going to the doctor because you think he/she will tell you it's "normal and you're fine" is absolutely the wrong answer. And having sex while possibly miscarrying? Bad idea. If you are pregnant and there is a chance of miscarriage, most doctors advise against sex (pelvic rest). Furthermore, if you are having a miscarriage and it's inevitable, sex during this time CAN cause infection and doctors advise against sexual activity for weeks after the miscarriage.
I personally feel like you seem nonchalant about the whole ordeal, and more concerned on whether or not you can keep having sex then anything. Which kind of sickens me, considering I've been through two miscarriages and was heartbroken each time.
I think the best thing you can do (for yourself, your partner(s), and your unborn children) is use a better method of birth control.