Had period 6 days later heavy period?

I started my period on june 18 then i ended on june 23 and it was a pretty normal period. then on june 28 i started another period..i was very stressed during that 6 day time. and it seemed like a normal period but this morning i woke up with severe cramps and back aches. and i had a long looking blood clot. it felt like another miscarriage but not as bad. but the pain still hurts. i am only 18 years of age. And there's always something wrong down there. in the past year i have had a UTI, and a yeast infection...now werid periods what's next? :/ Should i go to the Emergency Room?