What Are The Symptoms Of Miscarriage?

I am 2 weeks late for my period. i have had food cravings, sore/tender breasts and nipples, feeling bloated, nausea and sensitave to smells.. my period was due on the 13/05/2014. On the 26/05/2014 i had sharp pains in my lower back and lower stomach. When i went to the toilet i noticed a gooey clump of what looked like e/w cm with a drownish streek going through it ( it came out in a blob and stayed as a blob when i held it to look at it) then later i had a very light pink discharge and today the 27/05/2014 the discharge has a brown/pink colour with what look like blood clots, i noticed a clot that looked funny it sort of looked like a vein and had a bubble/blob looking part at one end. I have had cramping that comes and goes all day. Im worried that i might be having a miscarriage.. is that what is happning ?