If the outstanding mortgage balance on all your homes exceeds $750,000, your interest deduction begins to get limited. The limit is $1 million for homes purchased before December 15, 2017. Since you only paid $187 interest on a loan with a reported balance of $37,000 the calculation may have actually made it so that you are getting less of a deduction due to the small amount paid relative to the reported balance of the loan.
You said this was a home equity loan. If you did not use the money to buy, build, or substantially improve your home, the interest is not deductible and should not be included. If you did use it for one of those purposes, I would report the outstanding balance as $37,000/3. This is because you paid the loan off in April, so you only had the loan for 4 out of 12 months. Therefore the average balance is 1/3 of the pay-off amount.
