I don't think its over watering. You can see how the roots have started to grow up the side, so you definitely should invest in a bigger pot. she'll probably be really happy once you do that. It looks like you are planning to get a 10gallon container, so thats good.
It doesn't look like underwatering, but I would suspect that before overwatering because she has so many roots that it would be hard for her to have too much. the dirt also looks pretty dry and you said its hot out.
since you live in a hot climate you can probably get away with watering everyday. when it was hotter here I was watering everyday because my soil was so damn dry the next day. with the bigger pot you won't need to water as much though because you'll have much more space for water to hold.
good luck!