I was diagnosed with depression about 18 months ago when I couldn't face the school run and was reduced to constant crying with the anxiety of it all and the dread.
I hd talked to other mums who all, without exception, say that find the school run hard, but I get tht for some of us, it's not just hard, it's impossible.
Are you depressed. These days (after more than a year of counselling and 18 months of medication) I still hate the school run but I think I now hate it only as much as every other mum there who isn't depressed.
I try to turn up on time (I would turn up really late in a bid to try and avoid it, such a bad idea, my poor DC's!) and I stand in one of three places and only talk if I feel like it. Remember you don't have to talk. I always say hello to people though.
My DC's are Y2 now and I still loathe it, but little by little it has improved. I doubt I'll ever think it's (even) OK though.
My advice? Go and have a chat with your doctor if you feel the need and let them judge whether what you're feeling is normal or not. Also, don't feel obliged to talk, an acknowledgment of others will do.