Boyfriend is lying to me.

ash
so a week or two ago my boyfriend hung out with his cousin (who is a notorious weed smoker and has also done meth). he told me that he spent the night with his brother that night but a few days later I found out that he lied to me about that. then, this weekend he told me he couldn't come over because he needed to spend time with his dad. I had felt really awful that whole day and he knew it but never texted me until midnight. he tells me he's been with his same cousin all day and out of service. now today I'm finding out that he was actually smoking weed with him and was also high today when he told me. he lied to me. do you think I'm over reacting about being upset? it really hurts me that he would lie to me. who knows what else he was going there and not telling me.