No one's opinion of you matters but yours when it comes to drinking. Feeling like you let people down, disappointed them will only make it harder to have control. Keep trying. It's important to stay away from situations where people are drinking freely until you feel in control. I lost 20+ years of my life to booze...you cannot get them back.
And they are angels? Do it for you! As much as it upsets you that you're a disappointment to them remember sod them! You either have two choices stay on the booze and sod everyone or care about your health and do it for you! Remember being a disappointment to people is a guilt thing.. That will never get you off it! Their opinion doesn't matter.. They may worry but you have to do it for you!
If you feel bad because you can't stop drinking you need professional help. Ask your doctor and he may get you in contact with people who can help you.