I can't offer more than any of the posters have, but wanted to say you did an awesome job and should be proud. Don't allow this to overshadow your amazing accomplishment. Congratulations on a strong finish. Keep running.
Don't worry about your time, you're just starting out! Focus more on how you felt. Mentally assess what you could have done differently to better your race and try to correct it for next time. Get some races under your belt. The best way to forget about a poor performance is to get out there and race again!
Well yes, of course everyone is sometimes disappointed with their race times. It is like anything else in life. Stuff happens. Usually a runner will cover a distance faster in the actual race than in training, but not always. And with your first race the main thing is that you got the experience of the racing. There are a lot of factors to allow for - such as the logistics of maneuvering around other runners - that you are dealing with for the first time. Next time you will have a better idea of what to expect.
As for the issue of your foot going to sleep - I wonder if your shoelaces were too tight. Occasionally when my laces are too tight I start to get numbness in my foot.
Keep in mind that running is a challenging sport. If you train and run races on a regular basis you will have many difficult moments: moments of disappointment, and even moments when you wonder if you will go the distance. But the payoff is when everything clicks and you beat every expectation. You will have your moments of triumph that are worth all the pain and effort.
Good luck on your HM training!