It may be that you've just hit a sticky patch artistically - perhaps stresses from elsewhere in your life are just getting to you a bit and leaving you feeling run-down and listless. So don't throw your camera away just yet, you may find yourself reinvigorated somewhere down the line - besides, you're pretty handy behind the lens, so it'd be a shame to waste that.
As for being discouraged by other photographers, I know it's far easier said than done but try not to worry about it. In any field, there will always be people of superior skill and ability, but generally they only got there by sticking to it. If you stick to it, then you'll get there too. I realise these sentiments probably aren't anything new to you, but I hope they provide at least some comfort. *offers a cuddle*

Sounds like photo block to me.

Welcome to the Creative Club :P Honestly, it happens to us all. If photography, or any other creative outlet is how you express yourself, it'll come and go like all things we do. Sometimes there are dry spots, but when it rains, it pours.

Don't be discouraged and reject your creativity. If it's part of you, it'll be there forever!