There are many more reasons for abdomenal cramps besides your period.
Usually, cramps aren't anything to be too concerned about. Hormones, even when your periods have been fairly regular, can fluxuate all the same.
However, not being able to move for two days is pretty serious. While the occasional severe cramps are one thing, pain of that intensity isn't good.
I think it would be a good idea to call your doctor, just in case. There may be nothing wrong, but it is never harmful to check.