Your interest rate shouldn't fluctuate with the housing market, unless you have an Adjustable Rate Mortgage. Most people choose a conventional mortgage where you're paying interest on the value of the loan you received from the lender, not on the value of the property itself. You can voluntarily refinance the house to get a lower monthly payment if the interest rates go down, but if they go up, you're insulated from the impact except in the fact that you now likely have less mobility because having to pay a 7% interest rate when you are used to paying your 3.5% rate on a same-value house means you can't just sell and expect the monthly price you pay to remain the same.

Your taxes and insurance, on the other hand, do quickly balloon out of control if your property suddenly spikes up in value.