I wouldn't feel guilty about losing your temper while your dh was out of town - I suspect that most of us parents have lost our temper at some point, and most likely our parents did too and we all survived it. It's possible he's reacting to having had his father out of town, but I doubt that it's related at all to your meltdown.
Re this type of sudden change - it did happen to two of my children, but in each case it was related to something in their environment that was going on or had changed. The thing is, it could be any number of 18 million different things, or it might be nothing other than just going through a developmental phase. You're doing what you need to do - noticing that your child is behaving differently than usual, and trying to think through what has happened. You can watch for more clues - pay attention to when he's upset and when he's happy, see if you can see any pattern to what happens. My gut feeling, based on him not wanting you to leave the house etc, is that it's quite possibly related to his dad's temporary absence. If that's the case, he'll eventually regain his sense of security.
Hang in there!
polarbear
eta - fwiw, my children's innate personalities didn't really change from toddlerhood to teen (and I'm guessing, won't change as adults). They did have times like this when they were reacting differently due to something having changed in their environments, but in general, their basic innate temperaments were evident even when they were very little. The big exception is puberty. That through things out of whack in all sorts of directions... but only temporarily
