Am I in an abusive relationship???

So i realize that sometimes girls end up in an abusive relationship but they never know, mainly because they might be mistaken abuse behaviours for love, or care, or any other type that makes it hard for you to admit what's exactly going on?

I have been in a long distance with my boyfriend for almost two years now. I do love him. And I know he loves me. But sometimes, i feel like there's something off. For example, if we were chatting online and he wants to flirt and i follow up, he would reply in an instant and keeps the conversation going on, on the other hand if we were arguing about something or the conversation didn't go the way he wants, he starts ignoring my texts and replies after a while and sometimes it takes hours.. and i know for sure he's out there and he's online. When i ask him why he stopped talking, he'd just make an excuse out of nowhere and I'll stop questioning him because at that point it all seems ridiculous. Whenever this happens i keep overthinking about it especially when I know something about him from someone else and i ask him why didn't you tell me your were doing this or that, and he goes like "it wasn't worth mentioning".. lately he doesn't seem to like a conversation until it consists of sexting or sending pics to each other.. if we fight about something he would bring my mental issues right in front of me and blame it on my attitude and overthinking.. Am I facing some kind of an abusive relationship? Or am i just over reacting to this?? Please let me know what you think because at this point i can't help myself anymore..