Maybe with only 2 days it's hard for your DS to settle in? That when every Thursday rocks around it's like starting new again?
Perhaps try a picture calendar for the week which shows your DS which days he will be going to school?
And a picture book (involving your DS) of the daily routine on school days (wake, dress, brekkie, teeth, shoes, car, arrive school, play at school, eat lunch at school, mum picks DS up, go home, eat dinner etc etc.... You could read it to your DS each night and he could take it to school so he knows what's happening and that he will be picked up?
I also found routine worked with my boys once arriving at daycare. Pick something it the daycare centre before you get to your DS's room (eg a picture or sign)
And then focus on that each and every day as a 'warm up'