It's probably best to wait until you see your doc and have a talk about it. Normally, if you have a low-risk pregnancy then having sex is perfectly fine. Some women are advised against having sex due to risks such as: placenta previa(a low-lying placenta), having a history of miscarriages or pre-term labor, among other things.
My DH and I continued having sex early on but I didn't enjoy it as much as I should have because I was paranoid and tense because I had a miscarriage a few months earlier.