I think that one advantage of Glastonbury is the amount of options you have, but it does mean you miss other things you would have enjoyed. Also you get to try things out that you wouldn’t pay to see normally, sometimes that really works and other times you realise you just can’t connect with that particular band/ artist.
Some days I have been lucky to have a great run of stuff I have enjoyed and other days have been more hit and miss -sounds like you might have had one of those days yesterday, but today is another day.
At the end of the festival, if there is anything that I really regret not seeing , then plan to see them on tour or give them priority at the next festival.
I have missed lots of bands artists that I would have enjoyed- but didn’t know them at the time or because they clashed with something else, generally there is another chance to see them.
Even if you missed something great and saw something terrible instead, you were still out trying stuff out and experimenting with new things, which in my opinion are the ingredients of a fulfilling weekend.
Take care of you and please try not to put yourself under pressure.