That deal we had also used an escalation clause to be sure to beat other offers in a multi-offer situation, but there weren't any to exercise the additional $2500. 

This may be an academic exercise but will give comfort on how deep in the water you are in extreme situations.

But my dad who had gently nudged me into what at times felt like a ridiculous endeavor was also super conservative financially and convinced me to finance it on a 15 year loan.

Just sit down and have a gentle conversation and then let it be for a while. 

If I had my license, I would tread lightly- but push them back to their agent gently.

Here's what I do daily: - drink a liter of water with a scoop of wheatgrass as soon as I wake up (this helps me get ready for the day, wakes me up and hydrates me) - do some form of exercise - ride my bike around town, run, lift weights, play basketball, etc - read something - right now I'm reading a book on TED Talks to help me become a better public speaker - look at my vision board which is a big poster on my wall, the background on my phone and the background on my laptop (it would be impossible to miss it!) 

I would assume that option has already been exercised.2) I made a comparison.

It’s always a good exercise to review your ROI and your ROT (return on time).

Have you signed up for Tom Brady's nutrition & exercises TB12 program?

You should go physically inspect all of the big ticket items associated with the house (roof, water heater, a/c, etc).  7.5% is well and good for spreadsheet exercises but if the roof needs to be replaced yesterday, that's immediate capex that you're going to get hit with that you should add to the outlay cost.