To not go crazy for the reasons you mention, I retracted from seeing "giving" as something directly transactional, but as indirectly rewarding. An expat around here once told me that he gave a loan to a young guy, with a side phrase: "[...] I probably won't get it back, but that's okay, I never give anything with the expectation of getting it back."
That struck me deeply, and I kept it in mind with everything that I did for others. And still, I always find that everything I give, comes back to me multiplied, in unexpected ways. I hope that the same is happening or will happen to you :-)
I share what you comment 🌹. It is true, every moment is a gift when we choose to give, then, what comes for us comes back full of possibilities and gratitude.