My period was always on time and always lasted 6-7 days. Last month it was only last 4 -5 days, I don't think it was normal. And this month I haven't gotten my period yet (day 30). What's going on?

Unless it happens often and all the time, I don't think that it's anything to freak out about yet. Just keep track of your periods from here on out and if this keeps happening, consult your doctor since this has never happened before. If not, then I wouldn't think of it too much.