That depends. It won't hurt you, or anyone else, physically. But
1) how much money are you spending on it?
2) are you in a legal state?
3) are you putting it before a loved one?
4) is it affecting your work ethic?
Yes. Its not good for you and you will feel so much more in control of your body
Up to you but if you do quit slowly so you don’t feel the need to immediately go back on it