Wild 15 month old

Ok ladies I just need to rant. I’m 8 months pregnant with my second baby and my first baby is just 15 months. Anyway the 15 month old is driving me nuts. Literally. Sometimes he makes me cry he’s so bad. He has so much energy and is constantly destroying everything he gets his hands on. He’s got an attitude already and I’m not even kidding. He will defiantly tell men no and I swore I would never be one of those parents who spank their kids but honestly spanking is the only way to get him to stop the bad behavior. He has been testing me lately. Like I give him a warning before he gets a little tap on the butt. He deliberately goes out of his way to almost touch what I said he couldn’t or touch it anyway then quickly runs off holding his butt because he knows he’s going to get a spanking. I love his so much but he’s such a handful. I’m dreading when his sister is born. Sometimes he makes me question whether or not I want to be a mom and then I remember how much I love him. But he’s driving me nuts and I don’t know what to do. Anyone else have this problem?