Sorry for all the posts lately, this community is really helping me understand what may be going on with me. Glad to find y'all!

Anyway, after diagnosis of deficiency & 3 cyano shots in the last 2 weeks, I got ahold of some Jarrow methylcobalamin tablets as recommended here (and from a local store, too!). After having a weird reaction to my last shot, I was a little bit hesitant, so this first time I only took half a tablet. Put it under my tongue in the parking lot of the store, and in about 30 secs I realized I should let my wife drive.

Here's a rundown of how I felt, and the time since I put the tab in my mouth:
10 secs - like a slight jolt of electricity passing through me
1 min - feeling of rising energy
2 mins - more energy, starting to feel warmer
5 mins - feeling more mentally alert, vision seems sharper
10 mins - getting really amped up, but cleaner, less jittery than with the cyano
30 mins - by this time, i'm downright energetic, as I haven't been in over a month. Feel like jumping around. Heart a little fast but nothing bad. Very talkative, cracking bad jokes. This is a BIG change. All morning & the previous day I was dragging.
1 hr - after 30 mins raking leaves in the yard, still feel very peppy & giddy
1.5 hrs - after a little walk around the neighborhood, start feeling very tired
1.75 hrs - extremely weary, can barely move my legs
2 hrs - fast asleep (middle of the day), fitful but deep
4 hrs - wake up slowly, not energetic anymore but not as draggy as in the morning
8 hrs - better than yesterday! tired but alert, less jumpy, not as cold

Is it common to have this extreme a reaction to this stuff? I'm eager for more, but also a little concerned about the effects on my mental state and energy. I'm worried if I take the full 1000 mcg I'll jump out of my skin, then completely collapse.

Are the reactions a sign it's working, and I need it? Or a sign I'm taking too much?

My parents also take B-12 tabs, same dosage but cyano, their doc recommended mostly as precaution. They say they don't feel a thing when they take it.

Thanks everyone!