AIO- I’m not an ATM

I (37F) have been driving a couple in their 60’s to church for about six months. Let’s call them Renee and Steve. It is voluntary on my part, not too far out of my way and if I need to be gone for any reason, I can text and someone else will take them.
Within the last few months, Renee has started to ask for additional favors. One week it was a stop at Dollar General. Another time it was $5 for bus fare. Another time it was $5 to get Steve something for his birthday. She always pays back the money the next time I see her.
Last week, in her text to ask about a ride, she asked if she could borrow $10. I was out of town last weekend and told her as much. Yesterday, she texted asking about a ride again and again requested $10.
Thing is, it’s not a financial issue for me. I have $10 and have been known to blow nearly that on drinks and a snack. She has always paid me back, so it’s not like she’s running a tab. I’m just tired. I realized I feel like the mother of a teenager being asked for hangout money. I already messaged the person responsible for coordinating rides and asked if we can turn this into a rotation. I’m going to give Renee the $10, I’m just not feeling particularly cheerful about it.
Am I Overreacting to immediately wanting to say no to this request?