Boyfriend problems ?

Me and my boyfriend have been going through such ups and downs. One day he tells me I'm the woman he wants to marry and then he acts like he'd be fine if I didn't talk to him for days. I have been having an extremely hard time and we almost broke up a few days ago. Then tonight he went out with his friends and when we talked he was being so sweet and promised me he wouldn't drink, and he wouldn't act different. He's been out for four hours and I asked him to call and say goodnight and he was drunk. He lied and said he wasn't, that he hadn't been drinking. This isn't even close to the first time this has happened. Am I being too over protective ?