Re: Getting very discouraged, need your help.
You already know what to do. Leave aikido, start studying a different art and see what happens. After a period of time you'll decide to return to aikido or not return.
If you want to learn more aikido, stay with it. Maybe you're just burned out with your dojo and need to move to another one, perhaps a bigger one.
If you want to learn self-defense, join a school that teaches self-defense. If you want to learn kickboxing, judo, etc., join a school that teaches that.
Often people take a break from aikido (or whatever their art) for a year or two, then return to find that they're refreshed and relaxed and happy to be back. Others leave aikido to find that at this point in their lives they needed to start along a different path.
I sense that your real problem is that you feel guilty about wanting to leave your aikido dojo. If that's your real problem then focus on that, not on whether aikido is an effective martial art.
Best wishes for whatever decision you make.