I am going through exactly the same wave of emotions at this time. I go through them every year or two and eventually it fades away. There`s nothing that triggers them, it is more just something that grows quietly untill it`s too big to ignore.
Every time I`m afraid that it will be permanent, which drives me to do things that are out of my comfort zone. Usually that thing indeed ends up being travel or making plans to travel. I`ve learned to embrace it because it leads to big spurts of innovation and creativity, but eventually that feeling fades away and the whole cycle is repeated.
I haven`t talked with a psych, because it eventually goes away automagically, but I just figured that it probably wouldn`t hurt, so I`m going to make an appointment right now because of this post.
I can only say that I can relate with 90% of what you`ve described. If we`re going through the same emotions, you can be sure it can be diagnosed. Maybe you too should get some closure from a professional.
Good luck!