Spotting?

I know spotting can be totally normal during pregnancy, but I’m so confused! I’m 10 weeks and 5 days, saw the baby and the heard the heartbeat at 8 weeks. I had sex with my husband on Wednesday night (it’s Saturday now). When I woke up this morning I had light spotting that looked like old blood (brownish red) I didn’t think much of it since it was old and it wasn’t a lot. Then at breakfast I went to the bathroom and the blood was pinkish red, definitely not fresh and still very minimal. I had gone to the bathroom a couple times since breakfast and there was nothing and now, it’s dark brown so I know that blood is old. I’m having no cramps and I recently had a miscarriage in February so I know what that looks/feels like. Is it possible my spotting could be from sex or what else would cause it? Should I be concerned? I have my 13 week appointment on the 25th of October