When have you been knocked down and stayed down for the count? Have there been instances when you've just given up and just not bothered to get back up again? Perhaps you re-evaluated why you were fighting for that thing in the first place. Perhaps you realized that you really wanted to head in a different direction. Perhaps you just gave up. All of these are OK as long as you learned from the experience.
This is similar to the expression about never giving up - that the end might actually be just over the bend or the crest in the hill. We seem to want to give up when the going is toughest. After all, I wanted to quit the 314 mile Tennessee race with only 14 miles to go. That would qualify for quitting when the end is just around the corner so to speak. The difference there, though, was that I knew it was around the corner. Sometimes we just feel as if our tank is completely empty and we cannot go on no matter what. I was at that point for sure. Anyone who knows me knows that it is not like me to cry for 2 miles (or any miles for that matter) but that's the point where I was. My tank didn't even have any fumes left in it. This is one time where I would have been knocked down and NOT gotten up again. However, I had people around me that made me get back up (they just didn't give me any other option). Because of these other people I was able to finish. They pulled me up by my bootstraps. But the point is, it doesn't matter how you get back up, just that you do.
Surround yourself with people who will help you reach your success point - or even go higher than what you thought you could do. You may need to stop and take a rest but you should not allow yourself to stop forever. Some people may be down for years but they eventually get back on their horse and reach their goal. That is fine too. It has continued to spark a fire inside of them and eventually it got big enough to propel them back in that direction. Just don't tell yourself that you're down and out. Tell yourself that you're just taking a rest perhaps.
Do NOT stay down. Humans were made to be in an upright position. Get up and keep moving! You can do it. You don't really know what lies ahead of you and what greatness will be there for you to receive.