Playgroup Dilemma

Hi all, Just after a bit of advice as not sure what to do! I took my 26 month old son to the school playgroup this week, he already goes to the Mother and Baby group in the same place but obviously I stay with him for that and this was the first time he would be left alone somewhere from 9-11am. I was quite nervous about it but both Hubby and I had talked to him a lot about it, told him what would be happening, that Mammy would be leaving him but coming back after he'd played with the other children.and not to worry etc. So when it came to it, we went in, he went running off to play and the lady who runs it came over to take money, give me the contract and ask what I wanted to do about leaving him - i.e. how long I would stay etc. As he'd gone off to play so happily I said I'd rather leave sooner than leter as he knew I'd be going so didn't see the need to prolong it so I called him over, told him that Mammy was going now and he gave me a kiss and waved goodbye and went back to play! He was so good, I couldn't believe it so off I went.

However, at 10.30am the lady rang me at home to say he was quite upset and would I come to be with him which of course I did straight away. But when I got there, although he was pleased to see me, the first thing he did was take my hand and lead me to the little kitchen area and point to the floor, when I looked underneath the unit, I could see his little football had got stuck underneath and he couldn't reach it so I got it for him. Then he started gesturing with his arms that he'd lost something else so I asked him what he'd lost - turned out to be his teddy so off we went again around the room to find Ted. Once he was found, although he was still snivelling a bit after getting worked up, he was generally fine and we stayed for the rest of the playgroup. I didn't mention this to anyone as I felt like I was criticising them for not watching him and I know they can't possibly keep an eye on them all 100% of the time or go around fetching things for them. But at the end, the lady came over and suggested that next week I stay longer with him as he "obviously doesn't know them well enough yet" which is true - but I'm not convinced that was why he was upset - I genuinely think he got upset that he couldn't reach his ball and couldn't find his teddy but because he's not talking properly yet, he couldn't get the message across to them and then got worked up and wanted me as he knew I'd understand him. Because he was so good about me leaving him there, I don't really see the need to stay longer as he'll get used to be being there then and surely the whole point is that he needs to get used to the idea that I'm not there to ask which will hopefully encourage his language skills and confidence to approach others?? But I feel like she was having a go at me for leaving him so quickly, I really don't know what to do, am I being harsh on him/her?!

Any advice or comments welcome!