The world of art is a harsh one. When you draw, people will be mean and say you suck. No matter how many times you draw, or how much you improve, they will say this. What you need to do is suck it up, and try to satisfy those that hated it, hopefully they would tell you why (which they did in this topic), so you know what needs to change. Eventually, after enough fixing of things, you will be able to tell when it is OK to ignore the random jerks, and when to listen to others. Your goal though, is to try to satisfy everyone (even though it is impossible in the world of art). So, just accept this and it makes it a lot easier, and remember this every time you post something, and if you can't handle it, then this world is not for you.
Welcome to the world of art.
OH, and my suggestion mainly lies on; Try to spend more than 5 mins on it.