Yes, everything you described is normal. But if I were you don't set such large goals with the treadmill, just baby steps. Start with 3 minutes, and go for 3 days, then 5 minutes and go for 5 days. Then maybe do this twice a day...
I know you can do it...!!! you now have the power and the tools to be successful.
I'm inspired now to go use my weights...lol