"Strive for progress, not perfection" - unknown
When you get stuck on a question, on an assignment, on a subject, the best thing you can do is make yourself keep going! Don't let it stall your progress. Find something you *do* understand, you *can* complete, you *will* finish. Then come back to what you had trouble with.
Walk away for a minute, an hour, a day if you know you've gotten to the point where you are too frustrated to move forward. Ask for help, if you need it, then pick right back up and keep going! It's okay to switch gears or pause for a very short time, just don't let everything come to a screeching halt when you have difficulty.
You'll have difficulty - more than once, even! - but don't let it define the rest of your studies. You've got this!