7MGE oil pressure problems

[I h8 Hondas]

I have a 1986.5 Supra with about 158,000 miles. I was on my way home the other night and I noticed the oil pressure was slowly decreasing. No big deal. It wasn't dropping like a rock. I could have made it home if it hadn't started really falling when I slowed down to go through a little town. It had been running up around 3-4 kg/cm but when I slowed down it dropped below 2 kg/cm. Living in the U.S. I don't know how much a kg/cm is so I stopped and called someone to pick me up. Next day we took it to a shop which was only a couple hundred yards from where I lost oil pressure. A mechanic hooked it up to a pressure gauge that measured in psi. When it first started up it was running at about 70psi. Then it dropped down to 15. After that, as it kept warming up it dropped to 10 psi, which seems pretty low to me. But when you rev it up the pressure goes right back up to 70 and then back to 10. I've read some horror stories about these engines losing oil pressure and then ruining bottom rod bearings and/or crankshafts. So should I be concerned about this or is it going to be fine? It hasn't started knocking or anything yet.

Btw: As I was leaving the town I was visiting I had to pull out onto a busy highway and while looking carefully side-to-side I absentmindedly put it into third gear instead of first and somehow managed to not stall it. The bottom end didn't like this. I'm wondering if this mistake could have done my engine in.