Couch to 5K Week 6 Update

Yesterday I finished Week 6 of my 9 week program. I got a week behind due to weather, etc., but we're back on track now! Last week's workout was:

Brisk five-minute warmup walk, then: Jog 1/2 mile (or 5 minutes) Walk 1/4 mile (or 3 minutes) Jog 3/4 mile (or 8 minutes) Walk 1/4 mile (or 3 minutes) Jog 1/2 mile (or 5 minutes)

Brisk five-minute warmup walk, then: Jog 1 mile (or 10 minutes) Walk 1/4 mile (or 3 minutes) Jog 1 mile (or 10 minutes)

Brisk five-minute warmup walk, then jog 2-1/4 miles (or 25 minutes) with no walking.

I struggled on Monday and Wednesday but pushed through on Friday and completed the whole 25 minutes when I was running at a hotel. I notice that I do a lot better running indoors on the treadmill, but I don't know why. Next week is ALL 25 minute runs and I'm already nervous about being able to complete them outside on the track. I know it's something mental that I need to conquer, but I'm just not sure how...