Boyfriend

So I don’t really know what to do. I’m dating this guy, We are both in highschool and we have Been dating for almost 5 months. Lately we haven’t been able to have any serious conversations like it’s all small talk and if I even try and have a serious conversation he thinks I’m breaking up with him! Also he lied to me about FaceTiming this other girl! Please just give me advice!!❤️