Failing myself (Melissa)

So I really want to run a half marathon. I set this goal oh, about 3 months ago, and I am only at the point where I can run 3 miles. Even the 3 miles is pushing it. I feel like I am not going to meet my goal. I am starting to lose the motivation to run because its hard to be consistent and run 4-5 times a week. I don't want to fail myself. There is a 10k mid-October I'd like to run and I'm not sure I'll be able to get to running 6 miles. I can't come up with any excuses why I won't meet my goal of running a half marathon, but I really don't think I will be able to do it. I guess I will be okay with not running it as long as I weigh a decent amount less than when I started this journey. How am I going to lose more weight? Running. Ugh, it's a vicious circle. I want to be lazy and just relax and now I go back to work next week... blah, there goes any energy I had. This whole needing to exercise sucks....