So confused with this spotting/bleeding

ifoundmyromeo

This is my 3rd pregnancy and everything is so different.  Last Thursday my husband and I had sex and I woke up Friday with some brown spotting (light brown when wiping).  I freaked, went to doctors, and they heard a heartbeat (6wks).  They told me pelvic rest, but I looked good. I then went on to my normal workout routine, and after started having a brownish red snouty blood.  I called the doctor again, and they said to take it easy, no working out, and call if I had cramps or it didn't stop.  All weekend I had on and off light brown spotting.  Monday I went back in to the doctors for some reassurance and I got it, another heartbeat was heard.  Tuesday, I woke up again with the brownish red snouty blood which turned to light brown spotting which went away, and I keep having this pattern, comes and goes.  What is the problem??? I am freaking out I am going to miscarry or is this ok? I am not scheduled to have my real first appt till a week from Monday, which seems like a lifetime away.  I have no cramps, but sometimes have that dull achy lower stomach pain, like gas or stretching.  Any insight?