Red 3 Dilemna (Final Card)

I've been playing canasta for a good 38 years and tonight encountered something I have never had happen before...and I do not see a solution for this in the rules for any canasta variation.

I was playing cut-throat against two opponents. It was my turn, and I miscounted the remaining cards in the deck. Turns out there were five (5) left including the last red 3. It was my turn and I used up all of my cards and had no canastas and only two cards left in my hand, a wild card and my discard, so I threw one out.

At the time I had a 6-card incomplete canasta going for a natural, and hoping to draw on my next pick the missing card, or in lieu of that, making an unnatural and having a discard. AT least I would make 300 points for that round from the unnatural at minimum.

My two opponents went, and then it was my turn, and there was just one card left in the draw pile...the final red 3. I had only one card in my hand, a wild card.

The rules state that you must throw out a red 3 upon picking one up, but I could not do that as I also had to discard, which I could not since I only held a single remaining card in my hand.

It was agreed that discarding the red 3 into the discard pile, and ending the round with that deuce deducted against my table points, was the only way to go (no one had went out that hand).

Well, in 38 years I never discarded a red 3 intentionally before, so I have no idea if under these bizarre circumstances caused by my stupidly putting myself into a 1 card position with no canasta completed had any other solution.

Did I do the only action possible under the circumstances, or is there a rule that governs a bizarre situation like this ?

Thanks !!
Robert