Little freaked out

I seriously doubt my bodies ability to do the following, which is a shame because today is day 1 of week 4 and this is what's on the agenda:

• Jog 1/4 mile (or 3 minutes)
• Walk 1/8 mile (or 90 seconds)
• Jog 1/2 mile (or 5 minutes)
• Walk 1/4 mile (or 2-1/2 minutes)
• Jog 1/4 mile (or 3 minutes)
• Walk 1/8 mile (or 90 seconds)
• Jog 1/2 mile (or 5 minutes)

Obviously, I don't doubt my ability to walk for great lengths of time (thank God) and I now know I can jog for 3 minutes at a time. What's freaking me out is the jump to 5 minutes. It sounds like such a short time, doesn't it?  When you're in it, or when I am in it, it feels like its taking forever and I might possibly experience some sort of catastrophic blow out. Kinda freaked out about tonight.