Use stories to talk about struggling with emotions. Point out people's faces, and ask how different characters in the same picture feel about a situation. Ask her about which characters she identifies with the most and why. It will help you get good insight into what she's thinking and feeling.
We’re the same! As soon as she hit 3 she’s been much more emotional. Cries, clingy, sometimes takes herself to her room saying she wants to be alone - it’s like having a teenager! I just try to talk to her and see if I can help or give her a cuddle or sometime I give her space but it is a minefield!
Maybe a 'how are you feeling?' poster with few faces she can point to and you can talk about it. You can use it throughout the day, not just when she's upset, to talk about things that are bothering her and ways she can deal with those things. I think the best thing you can do when your kids lie on the floor is low down with them. I would clamp down on the screaming at you guys, though. Sad/mad feelings are ok; shouting at others is not. Remember, to her, each of these things is not the smallest thing. This is a great time to build your bond by showing you are there to listen to her and help her when her problems feel so big. Also, try to let go of the expectation that she should be happy all of the time. Keep in mind she may have a different energy than you, and feeling pressure from you to change may make her feel bad about herself. Some people really are more comfortable when they feel a little melancholy. "Eeyore, be Happy" illustrates this idea in a kid-friendly way.