I will be a ‘tipish’ and answer your last question first
Now- I personally think that feeling like a loser and being a sucker are worlds apart. You know my definition of suckers. However, feeling like a loser comes into the topic of “good and bad guilt”, which I’ve been meaning to touch upon for a while now. (Murphy’s Law- I don’t have ‘the book’ handy now, so I’ll do my best from what I remember.)
Good guilt is when you feel guilty or feel bad about having done something wrong, and to counteract, this guilt causes or propels you to do something good/positive.
as the slogan goes: Just say no!