Am I just not cut out to be a nanny?

I 21f have just got my first nanny job a few weeks ago, and feel so overwhelmed and burnt out I have no idea where to turn.

I am currently watching a little girl who just turned 3 a few times a week, and everytime I'm done I feel so shaken up and tired I don't think I can do it again.

The biggest problem I'm facing with her is tantrums. She's constantly throwing tantrums. She demands things from me and when she can't get them she screams and throws a fit. I often have to chase her around the house to stop her from destroying things, she'll throw or dump things onto the ground seemingly out of spite. Sometimes she's good, and will do whatever activities I've planned or play nicely but it's usually not for very long and then she starts demanding things again or throwing tantrums. I'm starting to dread everytime I go over to watch her.

On top of this the mom is a bit passive aggressive and seems to get offended really easily, which adds to the stress. I had made a comment about how calm her daughter was upon my arrival the other day, she's usually really upbeat and energized when I get there, and the mom gave me this super offended look and went quiet for a moment like she didn't quite know what to say. I feel like our interactions are always really awkward. There's been other instances like this too, which put me on edge whenever I'm interacting with her.

I just don't know what to do. I've always wanted to work with kids and still do, but I feel so overwhelmed. I can't tell if it's just because I'm new and still getting the hang of it, or if this is just a particularly difficult kid. Any advice would be greatly appreciated.