I've had irregular periods since I started having my period, and typically my period lasts 3-4 days and I only get it every 2-3 months. The longest I went without having one was 6 months. I started my period 2 weeks ago and its still going strong and I'm starting to get worried. It's very heavy and a lot of clotting. My period has NEVER lasted this long and I rarely get cramps, but this time I am getting some pretty bad ones. Also, I've been feeling a bit dizzy since it started, to the point where I have to sit down a few minutes to keep from falling. Typically I would go see a doctor for this but unfortunately I don't have medical insurance at the moment, so I guess I'm just looking for some advice or possible causes. Thank you.

Planned parenthood is in many states and they provide health care on a sliding fee based on income.
You need to see a doctor.
There could be any number of reasons for your periods being off cycle and to try to diagnose via the internet would be foolhardy.
Below is a link to follow to find a planned parenthood in your area.
Planned Parenthood