Why am I dizzy my dr told me I'm fine but I have anxiety can it bee from not sleeping a lot or diet I don't drink a lot of water?

Find another doc. You may be fine - and that's good, but you are feeling bad and that's important too. Your doctor may be really good at some things, but it seems how you feel now is not one of them. Go to someone else and do your best to change what you can. Rest if you can't sleep, eat as well as you can and do drink lots of water - make it vitamin water maybe. Get help so you can enjoy your life.
Check. There is no way to figure this out without more information. What is your heart rate? Blood pressure? Blood pressure while supine and while standing up? How many hours of sleep? What are your electrolytes on a blood test? It is impossible to provide an answer without more information. Check with your doc.