Am I crazy?

So, my boyfriend and I have been together for 6 years. We have lived together for 3 years and this last few months he's been pulling away from me I feel like. He's been doing nothing but playing gta online with people even when its our only day off together its like that's all he does. He's even started turning down sex lately.... 
Tonight he created an instagram which I have no issue with at all but when I asked why he created it, it was because one of the girls he plays video games online with was talking about it and wanted him to follow her. Now I like to think that I'm not a jealous person but I feel idk betrayed by him a little because he never seems to want to spend time with me anymore he spends all his time online with these people and I'm a little hurt I guess. It feels like he talks to them more than he talks to me, and he definitely has been spending more time with them than he does with me... I've talked with him about it but he always makes me feel like I'm crazy or something like I'm imagining all of this. 
Am I crazy? Should I just be okay with it I mean its just video games right? What do yall think?