Are Heavy Periods Repetitively Occurring Every Week Normal?

I have my period way too many times in a month, it would go for a full week in the middle of the month... like it normally should. Then would stop for a couple of days then start up full on period the next day and stop again the next day and repeat, it would be repetitive for weeks on end just coming and going every other day. At one point when I first noticed this weird cycle happening the week prior to this cycle I had a normal period, the periods that my body is used to. Then the cycle started and the way it started was it happened in the middle of the day then a few hours later there was blood pouring down my legs. I go to wash off and I take the tampon out and TWO HUGE blood clots fall out the size of my hands, and this has scared me ever since. The bleeding stopped the very next day and around a week later I got another pretty normal period which lasted for a week, then this whole cycle started where it would go then stop then go and stop. I m not on birth control, I ve never been to the health department in my life nor an OBGYN office. Is this normal for a woman 18 years of age to be experiencing?