No you are not over reacting. Every guy needs to show his girlfriend affection. If you feel like its not enough then let him know. That is his job. & If he isn't willing to do it, there are many others that would. Also, I don't think you should be too concerned. But if you feel like he is hiding something than simply ask him (in a non accusing way) "Why do you always take your phone with you to the bathroom" depending on his answer should then depend on what you ask next. If I were you & he were defensive about the question than ask him if you could look through his phone. If he gets defensive about that than wait until he's sleep to go through it. Its unfortunate you would have to take that measure but sometimes you need to to get the answers you want because guys are not straightforward.
I wouldn't worry about taking the phone into the bathroom.. everyone does that it gets boring just sitting there lol. But the fact that he's being less affectionate that's no good :( next time you are with him say your phone is dead and you have to text your friend and ask if you can use his then see what he says. If he acts sketchy or is like ill text her for you than you know something bad is up. Talk to him though about the affectionate part ask him what's wrong.