This isn't the most helpful information but if you believe you have nothing to offer, then that's what you'll project. You'll create that reality by believing in no other alternative. So just ask yourself if it feels true because it "is" or because you believe it to be - if this is not the life you want for yourself then your only alternative is to act like it isn't true. At least that way you'll give yourself a chance where there is none before.

I'd recommend seeing a therapist as it's a difficult hole to get out of alone.