Two periods in a month. Plan B side effects or am I pregnant? Please help?

If you had protected sex you didn't need to put all those fake hormones inside your body!
Even in total emergencies, it's not meant to be used more than once per month, as it's a huge amount of hormone. It can mess your hormones up for weeks, & if you've taken a double dose in such a short time, it's probably going to mess them up for several months, not weeks.
You could get any symptoms such as those that you get with a period, pregnancy, the menopause, or any other hormonal chance in your body.
It's just going to be a case of putting up with irregular spotting or bleeding, until your body gets rid of all the artificial hormone, & back to normal.