Should i be suspicious? Please help!

I'm sorry, i didn't want to have to bug you ladies with this nonsense but i am scared for my relationship. My boyfriend and i have seen each other mostly every day/other day for the past 8 months, but recently over winter break i've only seen him 2 times in the past 3 weeks. He's stopped texting me consistently like he usually does, usually says he was just sleeping or was with family, and that he doesn't like being on his phone much. so i tried to be okay with this, i understand being in contact 24/7 isn't necessary. the thing is, he's stopped trying to see me, make plans, sext me like we normally would some nights when we haven't had sex in a while (hadnt had sex in weeks either), all the old stuff he used to love, he seems to have lost interest. i saw him yesterday, and we recapped on what we've been up to during the past weeks; he told me he'd been hanging out with family and working on some music. i told him that i was getting weird vibes from him as of late, and he said what? like i'm seeing someone? which of course struck me as a little odd. nevertheless he reassured, promised and even SWORE he is not cheating on me. later, on the way to the mall, he pulled out his phone and i asked if i could see it (we use each other's phones for games and youtube ALL the time, never an issue) and he seemed caught off guard, told me no and slipped it in his pocket. when i asked him why, he said he just doesn't feel like it and that he doesn't have to show me. we get to the mall, i'm already fuming, and he goes to use the restroom, which i suspect he also used the opportunity to clear out anything suspicious. i asked him one more time before he went in the bathroom, and he still said no. he came back out and i wasn't talking for about 10 minutes, so he finally asks "if i let you see will you stop being mad?" YES BABE AFTER YOUVE HAD THE OPPORTUNITY TO DELETE EVERYTHING!! cmon i'm not stupid. i ignored him, and he told me he only said no to see how i would react -- if that were the case he would've just told me that the second time i asked! either way, why would he put me in that position at all? long story made shorter we got into an argument about privacy (when i never even mentioned anything about doing a sweep on his phone), told me he wasn't going to fall into a stupid little cycle in this relationship, i cried, we went to get food, he apologized and comforted me and all was well. we had sex later that night and then i had to leave, and i haven't talked to him much today because he went out with his family without his phone. i don't know if i'm just being paranoid of if maybe he is lying and there is something going on. if he is lying, i don't know how i would ever get him to tell me the truth, he's had trouble with it in the past. i know a relationship is nothing without trust, but i've given him chance after chance to regain my trust even after dealing with his compulsive lying and i don't want to regret that. what do you ladies think? am i over reacting or does it seem fishy?