My 3 year old is super clingy and I struggle even leaving him with his dad without him running after me screaming. We've been going to playgroup two mornings a week and I've had to stay with him the whole time. The last 3 times, I was about to leave him after 15 mins, until last week when he screamed so much I ended up coming back in. We've been going gently and it seemed to be helping him grow his confidence, but now he's gone backwards again and I don't know what to do. 
It's actually making me so anxious now I'm worried that for the next few years he'll continue being one of these kids who cry every single morning when dropped off at playgroup, kindergarten or school.
I'm not sure if I should just do the whole "tough love" thing now as he'll be starting kindergarten next year, basically it's the same as reception (but shorter hours luckily). We live abroad so it's important that our kids integrate and pick up some more of the language by going to at least some kind of childcare. (The language thing isn't what's intimidating him as we've been here for nearly 3 years and he is often around family who speak the language etc and understands somewhat even if he can't speak it.)