I can't tell you what your problem is, but I can list things and give you something that helps.
When you started back to drawing you might be starting with a huge canvas to draw something big or detailed. When you want to sketch up an idea, don't draw lines, just draw shapes, shades, and colors to get the basic layout. You can make that your next project to draw at least 10 ideas. If you don't know what to do, then scribble until you see something in the mess or think of an idea, or think of a theme. With a theme you have to draw a lot of different things you normally would see some place. Like things in a freezer, or on a boat, or shore, or on vacation, or in the yard. It is a scene drawing with items.
Anything you draw save it in a folder called ideas. It can be as wild as you want, nothing needs logic, as long as you draw more than one thing together. A lot of little things can be easier than one big thing.
If you do this enough then you will start to feel good and comfortable, because you don't need to finish anything, and how it looks is not important as long as you know what it is. You might see things you can improve on, or things you don't know enough to draw.
The best thing to do is find something your really passionate about, say cars, you have to feel it, that desire, that motivation to go after something. Its not that you are not creative your mind is not centered on your goals, for example visualize in your mind that you just drew say that 67 corvette that you have always wanted to draw, dont pick up a pencil yet, try visualizing for a few days several times a day, feel those feeling of happiness when its finally finished and you look back on it with pride. Focus is the key it doesnt matter what it is just pick something that you really love and focus on it will all your energy, dont worry about the steps in between your brain knows how to make it happen, just focus on the end result and it will happen for you. If this advice helped you out please help me out visit www.wix.com/lejprints/ljames and visit my comment section or my blog [link] the blog has some really cool art products on there that teach you how to improve your skills. Good Luck UrFallenAngel90