How fast am I going?

I have a huge problem.  I have absolutely ZERO idea how to pace myself.  No idea.  None what so ever.  I try so hard to pace myself on all of my workouts, but I always end up going so much faster than I should be.  I need help. Serious help.

As I started my tempo run today, I said to myself, "lets start to nail race pace for Boston".  I wanted to hit splits of anywhere between 6:57 to7:02 per mile.  This wouldnt exactly be a tempo run, but I knew it would be a good workout and help me in the long run.  I want to be able to control myself in Boston so I can finish strong and hit my goal time.  But my problem is, I have no clue how to slow down. 

My first mile I tossed out because its mostly downhill and its always too fast.  But I hit the mile mark at 6:27.  Thats waaaay too fast but I'm fine with that.  So I deliberately slowed down the next mile and kept looking at my watch to make sure I was on pace, and yet my mile 2 split was 6:44.  At this point in my run, I'm really getting pissed off at myself.  The next few miles had some rolling hills so I knew it would be a great way for me to learn how to control myself on the downhills and slow down on the uphills.  Problem was, I CANT CONTROL MYSELF.  I actually did a great job on the downhills and I didnt go too fast, but it was the uphills that killed me.  I kept going too fast on the uphills.  Not fast where it would drain me during the course of this particular run, but if this was a long run or race, I would be struggling to finish and catch my breath. 

So after 7 miles I looked at my watch and it says that I averaged a 6:44 pace over the 7 miles.  Thats about 2 minutes faster than I wanted to do it in.  Multiply that out over the course of a marathon and it would be too fast. 

Let me say that the run felt amazing.  I wasnt tired at all and I felt like I could keep that pace for a while, but I just didnt want to continue that fast.  Thats my problem.  I typically do my long training runs at or around race pace anyway, so my 18-20 mile runs I would to be at like 7:05-7:10 per mile.  However even during those runs, I'm still clicking miles off at 6:50-6:55 pace. 

I guess instinctually, I just want to go fast. Call me Ricky Bobby for all I care.  "I want to go Fast" and "if you aint first, you last".  So even when I say I want to slow down and use my runs as a training tool I cant.  I hate looking at my Garmin and seeing a slow mile.  It bothers me so much when I upload my workouts to my computer to analyze them and see a few slower miles.  Its all mental I know, but I hate it.  It bothers me so much.

How is it that you pace yourself?  What tricks do you use?  I need serious help with this so any help you have is greatly appreciated.  It's not that I'm complaining about being fast since that would sound crazy.  I just want to learn how to effectively train at the paces I want instead of what feels good on that given day.  I know if I continue this way, I'll end up burning out so I want to protect from that.