It seems to be the subjunctive mood, especially since it’s not known as a fact that “you” loves/loved “me”. If you read it as: I would support you if you

loved me. I don’t have the energy to support you/I love you. I want you to support me?

This page has some nice examples that help understand the different verb moods, and this excerpt seems most relevant:

The subjunctive mood can express a doubt or a wish using clauses beginning with “if” or “that”

Here, the first clause seems to be expressing doubt.