Am I the only "go to" person?

Let me say this first... I don't mind giving advice or helping people but I feel my kindness is being taken advantage of.

I'm married and I feel most of my time is helping others. So my mom & sister always come to me when they need advice or help with anything. From filling out applications online as my mom is not tech savvy, they ask me questions to Google for them, money when I don't have a job, I mean the list goes on.

Recently my sister found out she's pregnant (I'VE NEVER HAD KIDS, she has 1). She asks me questions about her pregnancy that I of course "Google". FF>> She says she wants my husband & I to be the godparents. Then she goes to say because godparents help when the parents aren't able🤔. Like my husband has a good paying job but I feel honored to be godparents, then my intuition is like.... idk about this🤨

It's like my phone doesn't ring until they need something. They may call or text here and there to check on me. I love them dearly. But I need advice on how to approach this... They also say things like calling me their secretary, then I laugh it off🙄

Not sure what room to post this in