Going on Alesse. What day to start? A bit detailed but would really like some help. THANKS.

On Alesse’s information it says you can start taking the pills the fifth or first day of your period. I really want to start taking them on a Thursday because I know from experience it’s the only day that will allow me to not have a period on the weekend. But what if the first or fifth day of my period isn't on a Thursday (it hasn't been for my current one but my cycle is not regular) Also my period usually only lasts 3 or 4 days (with brown spotting on the fifth). So even if my period doesn't last five days or the first or fifth day of my period isn't on a Thursday can I still take it then? I really want to.

p.s My doctors just told me to take a Sunday start. I did that on Tri Cyclen but I always got my period exactly over the weekend.