I'm about to go back on the pill... do I have to wait for my period to start?

I'm going back on Ortho Try-Cyclen. The options are for either a Sunday start or 1st day start, but one of the reasons I'm going back on the pill is because I'm so irregular. I don't want to have to wait until my next period to start because it could be months! Can I just start my pack on a Sunday? I think I have before but want to check...I'm about to go back on the pill... do I have to wait for my period to start?
If you are that irregular, talk to your doctor about giving you a short course of progesterone to jump start your period. That's what I had to do before going on the pill to regulate my cycle (I have PCOS). I took progesterone for 10 days, and got my period 5 days after I took the last pill. Then I was able to start the birth control pills as usual.
You are suppose to start them after your period has happened. Like I take mine after my period on the first Sunday.
It's unfortunate that you are irregular, but you are to start them on the Sunday after your period.