How do I get myself out of this Loop?

So I've this bad trait in me, that is if someone asks for cash i give it away without thinking and i mostly don't get back anything back in return, it's never really struck me this badly until lately. I'm a loner, I feel like people only approaches me when they need something to gain out of me, I would ask the cash but they'd have excuses most of the time(which would make me fold and say "it's okay, no issues") I can't help it, as I feel like people ask me as they are in need and I feel like I'm too egoistic to not give away. I'd personally welcome any helpful means to keep me out of this loop, really this is destroying me and as I learn no one finds me attractive enough to reach out to me unless they have soemthing to gain, it hurts even badly.