Could use some advice!

My son turned 5 in March. I’ve stayed home with him since he was born. He went to twice a week preschool (9am-1130) from age 2.5 until 4.5 when full day kinder starts here.

He started struggling at preschool just before he turned 4. He would scream and cry at drop off. Say he was going to barf, etc. It all started the week I told him I was pregnant with number 3 and his sister joined him at preschool (in a different class).

We worked through the issues with school with his awesome teachers and went to some therapy type place which helped him with his breathing etc to work through some anxiety.

He improved a lot once DS2 was born. He started school in September without issue and was happy to go until the last month or so.

He started crying at drop off again in June. He won’t do any sport unless my husband or myself are participating with him. He won’t go to a drop off party or a play date. His best friend came for a play date last week and he’s supposed to go there this week but is now refusing because he doesn’t want to go without me.

He’s a pretty challenging kid at home - emotional, hits his siblings. But if my husband or I are one on one with him, he’s incredibly well behaved and a joy to be around. He’s good at school - on the report card on the last day of school there was some issues mentioned we wish we had known sooner. Mainly that he “lacks confidence” and that he can’t sit still and stay on task sometimes.

Any one else have a sensitive/emotional kid like this? Specifically a first born boy? Someone once mentioned to me he’s very typical first born boy. And I would add to that he’s a very typical first born boy who has a stay at home mom, haha.

Looking how to get him over the hump for doing things on his own. He immediately starts bawling and making a huge scene if we try to make him do things without us (like we will be 10 feet away watching but he wants us closer).

Any tips or resources appreciated.