It sounds like you're in a crisis OP, and shaving ones head is something that often happens in such times as a means to feel like you're in control of yourself.
I think you'd regret it and the urge is a red herring. Shaving your head is unlikely to make you feel good about yourself and may cause employment issues etc, sadly.
Changes need to be long term goals, achieved little by little. I would have a sit down with a new pad and pen and write down areas of your life you feel are a problem, and do so positively.
Eg, if weight is an issue, see GP for advice, commit to a healthier diet full of things for good health, download couch to 5k and start slowly. Nothing you do will make you love yourself if you don't stop and work on being kind to yourself.
Changes CAN happen, you are the captain of your own ship. I would call samaritans if you feel urges to make rash changes based on feelings of self hatred, and go to your GP to be referred for some talking therapy. These are things that can make a proper difference to your life, a haircut won't. 