I adopted a 5 month old kitten back in September and aside from the normal adjusting and kitten behaviour everything was fine. He turned a year old in April and around this same time I noticed a change in his behaviour. Specifically, he started doing something he never did before and I am having trouble now getting him to stop this behaviour. It started one night, right after I fed him and I was going about my business as usual. He followed me into my room and then jumped up and bit my leg. It wasn't hard or anything, but he never did this before and I was surprised. I tried to gently say no to him, but he kept jumping up and attacking me. I think that I probably reacted the wrong way and may have been a little rough with him while trying to get him to stop. Since then this biting behaviour has gotten worse. At first it wasn't too hard, but then he started biting me even harder, as if he really wanted to hurt me. I have scars on my arms from his bite marks, but luckily I have always had long sleeves on so his teeth haven't really broken skin much, just scratched it. I don't know what started this behaviour and why he just suddenly decided I was a giant toy for him to attack, but it needs to stop. I have tried various ways of getting him to stop already, and so far no luck. I admit in the beginning it was getting me very mad and I may have reacted a bit too harshly, yelling at him a bit and even picking him up roughly to 'toss' him out of the room. But I have since tried to be patient and I even attempted the whole 'go limp' act, but that does not work. When I stop moving all it does is make him adjust his hold on my arm and then he bites down even harder! Making a loud noise like saying 'OW' in a high pitched voice also really doesn't work. It might stop him briefly, but he goes after me again after a moment of shock. And using a toy as a distraction is also only temporary, he still comes after me.
I don't believe he is doing it from a truly aggressive mindset, I just think he wants to play and he's letting out that energy the wrong way. He has never growled or hissed at me during any of these 'attacks' and after a few minutes when he finally calms down he is on my lap purring, so he obviously doesn't think he is doing anything wrong. Nonetheless, he is hurting me and it needs to stop. I don't have any other cats or pets, only him. I am home most of the time and I live with my dad, so he does get attention from either of us and we both play with him. Maybe he isn't getting enough play time? He doesn't always seem in the mood to play though, and sometimes when I do try to play with him he will just sit there and not move. But then 5 minutes later when I sit to relax he acts like he's ready to play. I really don't know what he wants or how to properly keep him entertained. He does have a lot of toys and he will play on his own as well. He also loves sitting and looking out the window, so that keeps him entertained too. He will watch TV sometimes too. I think maybe having another cat would help, but I can't afford that right now. What can I do to teach him that my arms and legs are not toys? It will become more dangerous for me soon when I'm wearing short sleeves in the summer. Please help. Thank you.