Valium every three days and dependency

I have a benign tumour in my throat which is compressing my vagus nerve and causing unbearable anxiety which I can't calm down. The only medication that helps is valium. I'm trying not to take it every day because the effect wears off and I don't want to increase my dose. I take no more than 5mg. It's hard to not take it on my off days but I'm trying to stick with every three days if possible. Does that amount cause dependency and make my off days worse? I really can't tolerate life without valium in my life.