Should I trust my gut?

I need your help, ladies. I'm with this man I've known since high school. He's very sweet and attentive. He buys me my favorite chocolates, gives me foot massages, and makes sure I'm taken care of. And for the first few months, I felt like a very lucky woman and I've loved being with him. But almost over night, it changed.

I started noticing his negative qualities. He's very arrogant, he loves to throw his money around, he can be very clingy (which I'm not a fan of). I started not to want to be around him and I've just got this deep gut feeling that him and I shouldn't be together. I don't know why this feeling has sprung up and I can't shake it. Any one else experience this? Should I ignore it? Should I talk about my concerns with him or should I trust myself and break things off? Any opinions are appreciated.