An early period does not necessarily mean that you are pregnant. The period could come due to various factors like hormonal imbalances, an ovary condition or a reproductive disorder like endometriosis. I would recommend you to visit a gynecologist for a checkup. You can read more on this, at http://www.livestrong.com/article/22195-reasons-getting-period-early/.
most people dont get their periods at all while they're pregnant and its very rare when they do. but in the extremely rare cases that they do,the periods are extremely light where its like spotting and its not much or for that long at all or anything. plus,if you havent done the "deed" then theres no way. you cant get pregnant without that 1 and only thing
You must "do the deed " to get pregnant. However, you can be pregnant and still have breakthrough bleeding. If you're still young, the timing of your periods can be all over the calendar. I wouldn't worry about this at all.
Girls can sometimes be as much as two or three weeks off with their period, it's not exactly normal, but it does happen. It all depends on sleeping patterns, stress factors, and hormonal change and a few other things. So if you haven't lost yer V-card, don't worry about it, it's normal.