Why am I bleeding during my pregnancy??

I am pregnant and I was at work and I started to bleed.. It really scared me because I had a miscarriage before.. But this time it was different the bleeding.. Ehrn I had the miscarriage the first time it was heavy bleeding and it was pouring out with clots and everything.. It happened on my first doctors appionment.. And this pregnancy the bleeding is light and it stopped when I got to the hospital.. They said it could be a threatened miscarriage.. They checked my hormone levels and they increased but not as much as it was suppose to.. So I came home and a few days later I took a pregnancy test and it still came up positive.. Well that night I had sex and I started to bleed again but it wasnt heavy.. It was more when I wiped I had blood.. Sometimes its darker like a brownish color and other times its more brighter.. Well since I had sex that day on and off the bleeding comes and goes.. I dont have pains or anything but I am worried… I also have an assist on my ovary.. So I get a little bit of pain from that… I dont know what to think.. Is thisbad??? Its been like 2 or 3 days that the bleeding comes and goes…but its not pouring out or anything and theres no clots… Its just really light bleeding… And another thing is I have irregular periods so could it be my period??? Please someone help me so I can relieve my mind.. My name is nicole and if anyone can give me an explenation or a educated guess you can email me at mznewyork19@yahoo.com thank you