I just lost a little buckling and can't figure out why. Any input would be appreciated. Here are the details.
Born 4/7, so 27 days old. Just finished first round of Corid. No vaccinations yet - that was due to happen this weekend.
He didn't want to eat at 3ish this afternoon. He had a couple of sucks on the lambar and then wandered off. His belly wasn't empty, but it wasn't tight full or anything. Around 5ish I went out to check on him and he was lethargic - standing, but not wanting to walk anywhere and definitely not playing. No diarrhea, peeing normally. His poop was sort of greenish and clumpy. Not berries, but definitely not loose or watery. I brought him inside and gave him a drench of baking soda. I thought entero, but was totally out of anti-toxin. (Shame on me.) I ran into town and hit all three feed/farm stores, but no one had any. When I got back he was going downhill fast. He was walking unsteadily, falling a lot and running into walls. He had a bit of clear nasal drainage and was obviously not swallowing because his chin was wet with drool. His temp was 105. I was thinking listeria or polio, so I gave him oxytet, BoSe and a fortified B with about 100mg of thiamine. He gradually lost control of all muscles, then started convulsing and finally died around 9pm. Poor little fella.
I'm thinking I should have used penicillin instead of oxytet. I was totally panicking and couldn't get a diagnosis figured out.. and then ashamed of myself for panicking.

I really couldn't justify an after hours emergency vet farm visit for a buckling, as guilty as that made me feel.
Anyone have any ideas as to what can kill that fast?