Last year, my Meyer lemon had three blooms. With each new bloom, the little lemons turned black and fell off. There were no lemons with the third bloom. I was a little late bringing the lemon tree back inside, so it's a little short on leaves. I fertilized it and now it is awash in blooms. What can I do to preserve these lemons and prevent subsequent blooms?
It sounds like you have a young tree; it takes them several years to be able to produce fruit reliably. Also, it sounds like this year you're getting a stress flowering - in other words, your tree has perceived that it's environment is possibly hostile so in a last ditch effort to reproduce, it's throwing all its resources into making flowers and hopefully some seeds. The tree needs lots of leaves to produce the energy to develop fruit. In order to have fruit, you need to have the healthiest possible tree. Here are some articles that will help you understand what your tree needs: https://www.gardeningknowhow.com/edible/fruits/lemons/lemon-tree-not-fruiting.htm