Cycle day 2 blood tests.. Help please

I'm totally starting to panic, my periods have been very irregular and near enough none existent so the gynaecologist has put me on provera for 10 days to force the period, I have got to go for bloods taking on the 2nd day of my next cycle (so the day after my period comes). 
I'm starting to panic as I take my last provera on Wednesday and I'm panicking as what can I do if AF doesn't show up until the weekend. I can see my 2nd cycle day been the Sunday.. Is there anywhere that does bloods on a Sunday? Anyone had this themselves?