Can't seem to run faster?

I have been jogging for 4 times a week for approximately 3/3 and a half months, and have been managing to go for about 3.4 miles without stopping for some time now and was starting to feel that I was getting somewhat fit. However, I simply cannot run any faster; I timed myself once and was so horrified at how slow I was going that I've been too afraid of letting myself down again (I averaged about a 14 minute mile). In each of my runs I've strived to achieve better times and pushed myself hard but I just don't seem to speed up. Is there anything I can do to see more progress?