Slow down!
Based upon your description above, it sounds like you've been pushing the pace of your workouts far too often. Were it that I was coaching you, I would recommend you work on upping your weekly mileage to half again or even double your current mileage; keeping the pace very slow until your comfortable with your current distances. If you do that, I predict you'll be delightfully surprised at how fast you are in a 5K and 10K races.
If you provide us with your typical weekly and monthly mileage, the types of workouts you do, and your typical finishing 5K and 10K times, I/we can offer you some more specific workout goals.