> I could just about manage covering all the expenses
You put literally all your income into non-liquid assets, taking on significant debt to do so. As you said, you had <5% of your income leftover at the end of the years. This is a lot of why you're in such a bind now. Even just held as cash, that money would be available to help you through this difficult time. Investing in an index fund would also have been fine, and would again be available to you now.
Landlording is a tough game. Don't you think?