My ds has been chewing the neck and sleeves of his clothes for the last few weeks.. this has tied in with an eardrum perforation/infection and some separation anxiety settling into preschool. I am worried I havecdealt with the latter wrongly and now he's nervy/stressed? He is a thumb sucker so definitely a bit of an oral fixator anyway.. he changed preschool and went from pt to full time (3h mon-fri) and two weeks in, his friend went away and isn't back yet. Anyway we cajoled and distracted a bit, I empathise and reassured, arrived early at collection time but one morning the door was closed and he was reaching for me 
He didn't cry and the v experienced teacher has said he was immediately fine and sent a pic of him beaming a few mins later.. but he's still dawdling a little at the door and chewing a LOT.. Any advice/knowledge/similar experiences much appreciated.