What to say?

So I just got out of school a few months ago and a couple weeks ago I started working at this shop. I like it, it’s right in my town so convenient I don’t have to drive. But it’s really slow there that this week I’m only working one day and probably only going to work one day for this month at least. He texted me that January I can work everyday but it’s only like 5 or less hours. But today I had an interview at another salon and I really liked it there. The shop I’m in now he’s old school so they don’t do anything besides haircuts. This other salon offers a lot of services that’d be more money and they’re really busy, is why theyre looking for someone. It seemed pretty promising about me being there. What would I say to the shop I’m at now if I get hired at this other place? I just feel bad because he’s so nice and he’s happy to have me there it’s just very not busy. And since I’ve only been there a few weeks. And at first I said it was fine me only being in there a couple days and it being slow. But now I really need the money. My mom and boyfriend have been helping me out so I can just go to school full time and be home with my son. I just need to start helping them out now and taking care of my responsibilities in general. I just don’t like confrontation I’m too nice and feel bad about everything lol and get nervous about it I haven’t been in this situation so I don’t know what to say!