The question, really, is what you would consider adequate proof of your helpfulness. Even if they were to confirm your helpfulness, they could just be telling you this only so you'd piss off already.
The issue is that you can second-guess anyone's true motivations. The most pessimistic estimates would imply that everyone you know secretly hates you for a number of reasons. It's important to recognize, for one's peace of mind if nothing else, that this is probably incorrect and most people are saying what they appear to be saying regardless of what your consuming self-loathing may tell you, because conclusions drawn from self-loathing are infinitely recursive and thus likely imprecise when not entirely wrong.
Now consider the possibility that I am just engaging in a bit of well-intentioned lying to assuage your fears of being generally shit. After all, I don't know you. I haven't lived your life. I'm just here to get a brief rush of that know-it-all feeling at the expense of people who might as well not exist for all the relevance they have to my life (thus incurring no cost or risk to myself).
That possibility, you ought to recognize, is probably just plain old paranoia and guarding against socialization. A hallmark of shut-ins of various stripes. It is one of those things you had best not worry about, because a world in which everybody genuinely harbors nothing but resentment and contempt for you is a scary and unrealistically self-centered place to live in.