I'm sorry to say that your basket case of emotions is totally normal. I was a total freakazoid in the beginning, and I still have my moments!
Are you sleeping?
Talk to your health care team about everything - your anxiety - your insomnia - whatever... I NEVER used to opt for drugs, but when I was hit with the cancer diagnosis, I was convinced that it was a good time to go ahead and take meds. I took xanax from diagnosis to about a week or two after treatment was finished. I have no regrets. I took it at night before heading to bed. It allowed my brain to calm a bit, which enabled sleep. Otherwise, I was sleeping about 2 hours a night... just agonizing about all things cancer related - including wondering if I'd see my child make it to high school.
The other thing I'll share is that it does get better. I hate saying - you'll find your new normal... But, it is kind of true. It still ticks me off that I can never be my pre-diagnosis self again - I mourn the loss of my innocence with regard to mortality... but it's true. You start to get used to it... and the anxiety drops back...
Also, when treatment starts, you'll feel like you have some semblance of control and like you're doing something... That will help as well.
Good luck. I'm so sorry you have to deal with a cancer diagnosis!