I usually have normal periods but last month I stated 2 weeks early. I started my next period exatly a month after that. I had what looked like 2 tiny chunks of meat on my tampon. Is there something seriosly wrong with me and why did I start early.

Honestly do not think anything is wrong with you. There could be a few possibilities why there was a change in your period.

Are you sexually active? Do you use protection?

If your truly concerned about the change can you see a medical doctor?

Do you have a mother or aunt that you can talk to, Issues with female problems is normal and nothing to be afraid of talking to with people like moms.

Also is there a school nurse that you may be able to discuss these things, if you don't feel good.

But periods are not "regular" as many young girls have been lead to believe, they can be a week early or a week late and that is your "regular" time. It is highly unusual for them to be at the same time every month for years.

As to the other parts of the question, again the issues of being seually active come into this.