What happened to the happy baby?

OMG Evie has turned into a terror the past week or so. Lots of tantrums when we're not doing what she wants to do and a severe mommy attachment when we're around other people. She even threw a fit when Grandma wanted to hold her. Makes for a very rough week on mom. I love this kiddo but I could seriously do without this behavior. I'm thinking it's partially due to needing a change in our nap schedule but I'm unsure how to change it. She seems to need MORE sleep, but she won't sleep more. It's a pretty consistant 10.5-11 hours at night and 3 hours worth of naps during the day (however she divides it up on any given day). This falls within the recommended amount of sleep for her age but she still acts really tired, complete with eye rubbing and yawning. If anyone has tips - feel free to send me some!