I keep missing my period every couple of months and they will last up to 2 weeks?

Periods: A normal period can last from one to seven days. The flow can be from spotting to around a tampon or pad and hour at the most. Periods that come more often than 21 days from start of one to another, last for more than 7 days, or are heavier than a pad or tampon in an hour on a regular basis need to be evaluated in the office. Hope this helps.