I was like that (and, still can be!). If it wasn't for the Run/Walk method (aka Jeff Galloway's method) I probably would have never ran further than 2 miles. I started out being able to run about 2 miles, but hating ever second. I just couldn't get past the 2 mile mark. Then found out about Jeff Galloway, and got his book. I swear, just knowing that I only had to make it through X minutes before walking, make it so much more bearable!!
The first week I tried the method, I ran until I started getting the "negative thoughts", but before I felt I HAD to stop. It was 1 minute! LOL!! So, I ran 1 minute, walked 1 minute for however long I was supposed to run for that training (I think I was training for a 5K). I quickly moved up to running 4 minutes and walking 1 minute...and maintained that for the first year or so. I remember it taking about 6 weeks before I could have a run that I actually enjoyed the entire time!
Another way to get over the negative thoughts, I set a goal for each run. Sometimes it's for speed, sometimes it's to run non-stop, sometimes it's to reach a certain distance, or maybe I do an interval workout and sometimes it's to JUST enjoy it!! No matter how slow my pace is! I did that this weekend, and I beat my current average pace by almost a minute per mile! I just took all the pressure off myself to "perform", and I ran faster and enjoyed it. Now...sometimes I slow down, but I make a deal with myself not to beat myself up over it.
One last tip...get an awesome playlist. Sometimes that can distract me. I have listened to the same playlist since I trained for a marathon 2 years ago...and I love it!! It's like 5 hours long, so I don't have to hear the same songs EVERY run, but there will be songs that come on, and I remember that race and it pumps me up! Sometimes a song that you have a positive association with can get you out of that negative mindset too.
Just be patient. You'll get there!
Patience and Fortitude - Mom