I'm having a tough week with my 9.5mo DTs.
They used to have 2 good naps, first at 9.30 for 1/1.5 hours and second at 2ish for 1/1.5 hours.
This week everything has gone tits up! They wouldn't take the morning nap so I tried to make it a bit later. That didn't work.
Yesterday I went for broke and kept them up until after their dinner. They went to sleep about 12.30 but were both wide awake by 1.40!
I had to put them to bed at 5.30 which was ridiculous because they were wide awake and ready to party at 4 am 
Today they've had a short sleep from 11.10-12 and despite most certainly being tired they're up in their cots laughing and singing for the past hour.
I'm feeling very anxious. I'm due to go back to work in a few weeks and I'm worried that their minder (a lovely person who will also mind their 27 mo brother) will find them too much to handle if they don't have a good nap.
Any thoughts or ideas? I promised myself I wouldn't stress over naps but this is really getting to me.