Sometimes a baby will cry and you can't figure out what to do to make the crying stop. That's not CIO, that's just life with a baby. I know it's hard, really! My child cried for the first five months of her life (like, all the time. I have no pics between birth and literally five months old because she never. stopped. crying) and it was awful. Big hugs.
I do think she sounds overtired. What time do you normally start getting her to sleep? Try a half hour earlier. It's so tempting when they're small to just go with the flow, and I am not not not!!! suggesting you impose
a schedule, but if there's a flow to your days, especially your evenings, it does help. It's never too early for a bedtime routine. This isn't something you rush, it can be a good hour leading up to bedtime (bath, quiet time, lights low, singing, etc). If your baby is still melting down, start a little earlier or just keep on with your bedtime routine.
Our daughter has never been a good sleeper, but as I tried everything, adapted over and over, have read EVERY BOOK ON SLEEP IN THE KNOWN UNIVERSE, and have the benefit of hindsight, I'm hoping we can make it easier on our next one (should this one ever go to sleep and let us make a "next one"
Bit big hugs. It's hard when your baby cries, but you will figure it out. You're responding to her all day and night and doing everything you can. I don't think evening difficulties are going to hurt her in the long run nearly as much as they hurt your heart right now.