Offshore - yes, but where were you? What's the air and water temp? Sailing alone involves some risk, but one has to consider the worst case scenario.
I have sailed alone, but not at much risk. I did head out a few weeks ago and found I was the only one at the site. 20 to 25 knot side off shore winds, air and water at 50 degrees F. Worst case would have been an hour drift / float / swim to the down wind shore of the lake. I decided not to chance it. I would have survived (good wet suit, hood, booties & gloves), but didn't want to risk the hassel. It can get lonely out there.
I did get a good day yesterday in similar conditions at the same site, but had 12 buddies to share the fun.