My phone says I have no storage and my photos do not want to load and my phone is acting up. What should I do?

I have no storage on my phone and it is acting up. It does not let me open WhatsApp or other apps. I have been deleting apps and photos. My phone is almost empty and nothing is happening, it keeps saying I have no storage. I am trying to delete pictures but It does not even let me see the pictures or videos because it has the little cloud or a circle with an exclamation point and they are not downloading. I can't even post any pictures on my social media. Sometimes I open my email and all of a sudden it exits out. I have to turn off my phone at least 7 times a day depending on how much I use it. I don't know what else to do.