he stopped saying i love you

i’ve been dating my boyfriend for 4 months now. everything has been going great. of course we’ve had our ups and downs but we always figure things out in the end but this past week i’ve noticed that he stopped saying i love you. if i say it to him he won’t say it back and i’ve asked him if everything is okay and told him i’ve noticed he hasn’t been saying i love you and he didn’t really say much. after getting a little drunk last night i asked him if he still loves me and he said of course i love you. i can tell something is off but i don’t know what to do. any tips?