Abnormal periods are cause enough to go to a gynecologist. There are several causes to this, like hormonal imbalances and things like polycystic ovary syndrome.
The blood clots are probably not something that would cause too much concern, but I'd bring it up with your doctor either way. That said, be aware that in your period, you're not only shedding blood, but also the endometrium, which isn't so much the lining of your ovaries as it is the lining of your uterus.