Of course without going to the doctors you cannot be 100% that you're not pregnant, but assuming you're not.
This is very normal. It happened to me exactly as it happened to you. A side effect of birth control doctors rarely tell you about is how much it can mess up your cycle when you go off birth control. It can take quite a few months to get back to normal, but you shouldn't wait forever.
Go to your OBGYN have them test you for pregnancy then if its negative tell them what's going on and in all likelihood they will put you back on the pill for a month to try to get your cycle going on its own again.
It took me 6 months almost but my period is finally back where it should be, nothing to be terribly worried about.

If they did put you back on the pill, it wouldn't be Yaz so don't worry about that.

If you decide that you still want birth control without the side effect of mood swings and depression, then try a different pill and tell your doctor about any negative side effects.

I have been taking Yaz for a little over a year now and all of a sudden I am having all sorts of symptoms of being pregnant. I have taken 3 tests and they all came back negative. My gyno told me to stop taking the pill because it could be side effects to it. I quit the pill almost 3 weeks ago and haven't bled which the gyno says is not normal. Whats going on?

Because you have been on the pill for awhile your bodies trying to regulate itself. Which in all honesty it could take a few months. Also when you period does come back that may be a bit off as well, you may have your period a couple time a month or maybe just a slight one at first. Birth control can do some crazy things to your body after quiting.