MS in Mathematics, having trouble finding work outside teaching algebra 10 years ago, I got an undergraduate degree in IT/CompSci from a good school. I spent most of my hours playing video games or drinking beer, and learned only enough to get a barely passing GPA. I never used the degree, as I joined the military and did the minimum amount of time for my paid education and got out.

7 years later, in 2016, after traveling and busing tables for a couple years, I realized that I had been wasting my life. I realized that learning is cool, and that I'd wasted a great opportunity both to learn interesting things and to have a rewarding career. So, I decided to go back to school. 

I applied the graduate Math program at WVU, for no other reason that I got a B in Calc 2, one of my highest grades in undergrad. They let me in even though my undergrad GPA was abysmal (2.5 or so), and that I didn't have any of the prerequisite math classes to get in. I agreed to spend the first two semesters taking undergraduate differential equations, basic linear algebra, proof writing, etc. After that, I started taking a full load of graduate courses. After three years, I survived to get a piece of paper, but having retained little actual mathematical ability. 

I was exposed to a lot of math, but because I was so far behind the learning curve, very little of it stuck. I was too busy trying to pass/survive to be able to learn much. What I did pick up lies mostly in the realms of numerical methods and differential equations. It is important to note that I learned almost nothing, even in these two areas. I graduated this summer, and can only talk in very vague terms about what I was exposed to. 

Now, I am unemployed and wondering why I ever gave up waiting tables. I can program a little. I can read a math textbook without my brain exploding, and that's about it. 

Now, I spend about 10 hours a day reading textbooks on ODEs and Numerical Methods, as well as working practice programming exercises from Project Euler and sites like it. I'm slowly working through Khan Academy's probability and statistics courses, as I never learned any of that in school.

It's dismal. I'm depressed because I worked so hard to try to bring myself up and correct a life time of laziness. I'm still working at it every day. My wife goes to work, and I read until my eyes bleed, occasionally checking my email for the most recent employer rejection letter. Now it seems like I should never have left waiting tables. 

So what's the question here? This:

What do I do? What do I study, and how long is it going to take before I know enough to be marketable? 

I can teach community college, but the thing is i loved the stuff that was covered in school, and I want to apply it. Sad thing is, I'm too dumb to get a job at anything but teaching algebra to bored college kids who don't want to be in class.
First of all, jobhunting s u c k s. It sucks even more when you're trying to get into a field and it sucks further if you're not in a major metro area. It's a massive timesink with terrible ROI, but it needs to be done in order to get a job at all. The truth is that whether you get hired isn't going to just depend on your skills and experience, but also on whether the person reading your résumé thinks your skills and experience line up with what they think they want, and you don't have a lot of control over that. So honestly it's impossible to predict how long it will take before you find something.

That being said, your situation really doesn't sound so horrible to me. You're interested in and studying things that (1) you want to do and (2) employers are looking for. You have a master's degree in a marketable field. As for whether you feel you learned much during your degree, it sounds to me like you're just in a bad place with a killer case of impostor syndrome. Some employers might want to see your transcript, but they're a lot more interested in what you can do for them. So maybe try putting together a portfolio of the kind of work you want to do, which might include models or software that you developed or small projects that you did for free or for cheap for someone. (These are pretty standard suggestions.)

Finally, you can't be everything to everyone. It might feel like you need to cast as wide a net as possible, but it sounds to me like you might be spreading yourself thin and that's contributing to your frustration. Narrow it down some by considering where your best bets are in your geographic area and what you really want to do. For example, if coding is the right path, then back-burner the modeling, or vice versa. Good luck.