Have you ever went on a solo vacation? What was the experience like?

My birthday is comimg up soon and I'd plan on spending 3 days at an all inclusive hotel with a friend but she completely blindsided me this week by telling me she'll no longer be able to make it due to monetary reasons. We have been planning this for months. I honestly haven't recovered and have been hurt but I am thinking about going alone and at the same time, its just all so nerve-wracking as I honestly don't wanna celebrate my birthday alone but on the other hand, with this new journey I'm currently on, it could be liberating.

I just don't know how to feel.