Frustrated

I'm going to warn you, this post is a stream of consciousness and more ranty than I usually like to be.

I've been very frustrated the last couple of weeks when I exercise.  Between sciatica, running cramps, clothing issues etc... I've been feeling like every time I exercise, something new bothers me and I hit that wall really early.
I think that's also why I haven't been posting much lately... its not as motivating to post about my 1 mile run where my running cramp was so painful I wanted to puke all over the machine (sorry to give you that mental image).
So what do you do when you hit that wall?  How do you recover and push past it?
I'm still trying to figure this out.
I've scaled back my goals for going to the gym.  I'm back to, "just spend 30 minutes on a treadmill doing whatever" so that I can at least feel like I've accomplished something.  I also am just trying to push myself to keep going and not get discouraged.  Shit happens, right?
It's still really off-putting to go to the gym and come back and feel like I did nothing.  I may as well have stayed home, but now I'm just sweaty enough to need a shower, but not sweaty enough to feel like I did anything.  This middle ground builds up frustration for me.
I've never been the kind of person to be like,  "eh, try and fail, its cool." I don't like failing.  I really don't.  I actually would rather not try.  As my friends know, I do not like to try new foods, because I'd rather not try them and learn that it was the most disgusting thing I've ever had.  Fortunately sometimes, I try new foods anyway, otherwise I'd still be on my pasta, doritos and breaded chicken diet from when I was 7.
This whole exercise experience has forced me to deal with "failing".  I know it's not failing and I know that every day is going to be different, but I feel very frustrated right now while I'm constantly hitting this wall.
I've been running for 9 months now, I can run for about 15 minutes at a 10 min mile pace before I'm exhausted.  I can go a little further than that before I'm really done.  I'm pretty proud of that because when I first started, I couldn't run down the block without feeling out of breath.
But right now, I run on the treadmill for 6 minutes and my back hurts, or my muscles start cramping, or my sock slips down in my shoe etc etc.  It's very frustrating because it feels like a major setback.  I worry that not only am I encountering all these issues, I am also losing what I've spent 9 months building up.
I think this is also why I'm so ADD about everything - I hit a wall and need to switch things up.  Yes, fitness experts, I realize that this slows my progress because I'm trying to do 100 different activities at once.  Instead of getting really good at running, or cycling, or weightlifting, I'm getting slightly better at all of these things.  Very slowly.
Which makes issues even more annoying because I make slow and steady progress, but can lose it very quickly when something crop up.

So my resolve for the next couple of weeks is to just keep going to the gym and to just keep working out.  I need to just keep pushing through this wall.  Everyone has their good days and bad days.  I am also using my one month Living Social deal at NY Yoga, so I'm trying to do yoga 1-2 times a week too, which is very restorative.  Instead of replacing my runs (which is what I did this week) with yoga, I'm going to add the yoga in and still do the running.  I can't hide from my problems and taking a break doesn't make them go away.  It would be one thing if I had a strained muscle and I needed to rest, but sciatica is not made worse by exercising, and muscle cramps are going to happen when they happen.

Do you get frustrated about exercising?  Have you hit a wall?  How do you get past it?  What do you do for muscle cramps??