Is he hiding something ? :/ rant

I seen my screen name pop up on my boyfriends phone today from snap chat and it said my user name but normally it says "my world " we both changed each other's name in our phones when we got together I didn't really want to make it a big deal or seem clingy for asking or saying something I'm only 17 as of Friday & hes 19 and he and I live together I haven't started my senior year because I feel like he'll be upset if I go he tells me he won't and that he supports me I'm just afraid to loose him I've started putting myself second to a lot of things I've messed up my trust / relationship with my dad and my mom for him I know it sounds dumb but I really love him & I honestly do feel like I know what love is I guess this post turned out to be a little more then just the phone thing but any advice will do