Like others have said, feelings aren’t right or wrong. Feelings are what they are. It makes sense that you feel this way given how stressed out you are.

That said, if is the primary breadwinner and she is still getting paid during her vacation, it sounds like she is doing her part to contribute to the family. If you usually work and have a master’s degree, can’t you find some kind of job to do during the day when the kids are at school? Since the change in finances is due to a change in your employment, doesn’t it make sense that you would shoulder more of the burden for making up enough of that lost income to pay essential bills? It also doesn’t seem to make sense that everyone else on the trip would change their schedules just to accommodate you. Since your wife decided to go, it’s not even her that thinks the timing is a problem; it’s just you. But you aren’t paying for or involved in the trip, so it doesn’t really make sense that you would get to determine their timing.