Could Heavy Bleeding In Pregnancy Indicate Miscarriage?

Hi, i have just found out i am about 4/5 weeks pregnant with my second child. but 3 days ago i started spotting didnt think anything serious,but the last 2 days it has got heavier almost like a period but not as heavy as i usually am there has been no huge blood clots just small ones. i had a miscarriage about 4 months ago i am scared that it is happening again