Re: Irregular Periods
Yes, it's completely normal. I had irregular periods too, and it was really frustrating... I'd never know when I would get them. I'd skip a few months, and even if I had it for 3 consistent months, it was always a random number of days between them.
Just like someone else said, stress, diet, meds... They all affect your period.
The only thing I'd worry about is that you are 18, and, by then, they should be a little more regular... But I don't think it's a big deal, so don't worry.
But, I would go to the gynecologist anyway, just to get checked out. You're 18, which is the perfect age to go. Ask her about going on the pill.. It helped me a lot. And cleared my skin, and gives me birth control, and gives me lighter and consistent periods.