They can put you on some birth control pills, to even out your periods as well, if your not pregnant that is.
I agree with Spade but I wanted to also add/ask if you have seen a Dr. about your irregularity? That would alarm me. That is not even close to normal.. I think you shoul dschedule an appointment with an Ob/GYN asap to discuss your menstral issues and they can do a pregnancy test there. Good luck and keep us posted.
Yes you can get pregnant if you dont have periods on a regular basis. A home pregnancy test will be reasonable accurate about 2 weeks after possible conception.