You are very clearly lacking in endurance based on your 3200 and 5k times. You should probably keep the long run where it is, but maybe make it more of a workout. if you are simply going out and running 10 miles at an easy pace, try every few weeks to maybe make the last 5 miles a fartlek or try to make the run a good negative split. You definitely need a tempo, at least 20 minutes, but probably building up farther from there. Don't do like a crazy long tempo, cap it out at about 40 minutes max. I would say to maybe replace one of those short interval sessions with something longer, like 1k repeats or mile repeats or something like that. Breaking 5 should not be difficult once you build up your endurance a bit more, you will feel 10x better in the second half of that race.