fourleaf - not sure if I've answered this thread before, but my DS is nearly 17 months and has been going to nursery 3 mornings a week since he was nearly 1, so coming up for 5 months. I had no other childcare options (no family nearby, childminder who has him the other 2 mornings couldn't take him M-W), so had to lump it. He SCREAMED every morning for the 1st month, then every afternoon when I went down to feed him. By the 2nd month, I was walking away from nursery and could hear him stop screaming so loudly, so knew he was settling. I was able to come and observe him a couple of times too, without him seeing me, and he was having a whale of a time. Then he got an ear infection, and drop off was bad again for a month. By the 4th month, drop off was great, he was running in, not even acknowledging me, and beaming at his key worker. This week, for some reason, he's been a bit clingy with me, but is running off happily when distracted, and he doesn't want to some home in the afternoons.
Nursery did say to me that the fewer sessions a week, the longer it takes to settle, but he is happy there now - and I know the staff, and am happy with them.
Can you drop off a bit earlier, or stay a bit longer and play with him in the mornings, just until he is more settled? I find that the happier I am, the happier DS is - so if I play with him for 5-10 minutes, and we're all giggling, then his key worker will take over and I slip out the door - doesn't always stop the yelling, but it mostly works!
With regards to sleep, my DS wouldn't sleep at nursery initially, but is now going to sleep on his own
for an hour in the afternoons - not as long as at home, but what an improvement! They did put him in the pushchair to get him to sleep for a while, which worked well too.
good luck :)