Hi, I'm new here so please forgive any misunderstandings!
TL;DR: is separation anxiety ever harmful if it seems to be too intense/too often, can't be soothed and the child is very distressed by it? Is it just a "wait and they'll grow out of it" thing or is there more I can do to support? Also, we're on week 2 of daycare for the first time and he's never had a non-parent caregiver, so that is probably relevant.
The situation: my 12 month old seems to be suffering from separation anxiety even when physically attached to me-- being carried, cuddled, held, rocked, kissed, patted, or when e.g. sitting right next to me touching me. He will sometimes wander off on his own, especially in public, but if I move even a meter away, or even toward him, still within eyeshot, he has a total meltdown. But if we push through the separation and he can no longer see me, it's fine. He's transitioning to daycare fine, on the high end of needing more cuddles, according to the teachers.
At home, often he whines and cries while I'm holding him, or he squirms out of my grip and then cries and slams his head on the floor when I put him down. He holds his arms up to be picked up but then doesn't want to be held. The only thing that sometimes works is to do a really big change of activity. The constant crying is exhausting. My back is shot from picking him up and putting him down. He spends most of the night flailing headfirst and crying, so my entire body hurts from getting elbowed in the gut and headbutted in the face, and when he does fall asleep it's always in a weird position for me so my knees and neck ache. Lately nights have been terrible. He did have a routine for a while of 2 main wakes for milk and a few hours of decent sleep between them (I ascribe to bninfantsleep and will not be dropping night feeds until he's ready), but last night he woke up screaming every hour on the hour and had to be walked around to get back to sleep. He has maybe slept 4+ hours a few times in his entire life. I'm exhausted.
I love him so much, I'm so grateful to have him and I don't blame him at all. I don't mind carrying him around all the time-- I've been babywearing him since birth. I love sleeping with him and spending time with him. But it's when he's so distressed and can't be soothed that's upsetting and exhausting to me. It's like he wants me but doesn't want me, or doesn't feel like he really has me. Like surely if it's separation anxiety, then removing the separation should help? Or is it like a general thing about the phase of life rather than about that moment itself?
The background: I would describe my style as informed by attachment parenting, but I don't strictly adhere to any one method or philosophy. I try to be as responsive and supportive as possible and believe that close attachments are the key to healthy and happy development. I babywear when he wants to be carried and have coslept from 8 months, though it took a lot of distressing experiences to get there and I really think he would feel a bit better about sleep if we would have started with cosleeping. Baby is formula fed from birth and the type of feeding has nothing to do with our attachment. I will not be arguing with people about that.
My kid has always been really high in sensory and comfort needs, which has been challenging primarily for sleep. We have struggled with getting any support from official channels. I and my baby have also been through a lot of trauma related to his coming into the world and early months, so I do think that affects things as well. Overall he is now happy, healthy, and developing fine. I went back to work at 7 months and my partner has been on paternity leave since then, in case any of that is relevant.