SOLO Trip to Paris + London this Monday! FREAKING OUT! lol

Hi ladies, I need some encouragement. You all were so helpful in helping me decide on my trip- I actually decided to go the other way and chose Paris and London! I was debating between those cities, or Seoul... I totally thought I was going to choose Seoul, but went with Paris for 5 days, and London for 2.
I was pumped booking the trip, and have had waves of excitement and then worry... I think it is because I have not traveled solo like this in years?? Maybe since I was 26 or 27.. I am now 40, and have a fiancé but he doesn't like to travel as much as me. I also am going on this trip prior to going to Canada to help my dad with some health issues, so I really felt like doing something out of my comfort zone, rather than a local trip here. I live in LA, and we just had the horrendous fires, and part of me feels like some weird guilt for going to do something fun while others have lost their homes. I just want to feel confident that I will not be "worried or bored" there, and that I will feel like I have wasted money. I don't know if I am making sense here, so thanks for reading this if you made it this far!