Does my cat hate me?

My older male cat has been acting a little differently since I got back home and I'm not sure why. Physically he seems to be normal - he's eating, drinking, using the catbox, cleaning himself, being vocal (he meows a lot when I pet him because he just seems to like to meow), and loving his treats. So that's all good and well.

But he seems to want to be away from me...if I pet him, he makes these annoyed meows rather than his usual happy ones. He also stays in the basement all day when before, he'd occasionally come upstairs and lay on my bed. He's not sleeping more than usual...just not coming upstairs.

I wonder if he's just upset with me...I was out of town for two weeks in June, came home for just a few days, and left again for two more weeks this month. Is he mad because I left? This perplexes me as a possibility because when I was in college, I was gone for months at a time and he was fine.

I brushed him earlier this evening and he was purring and enjoying himself, so that's good. Should I be worried? Should I try and give him extra attention, or just let him brood since he doesn't seem to want me to pet him anyway?

Other possibilities I thought of include the dog annoying him and discouraging him from being upstairs, or possibly it's just too warm for him (it's cooler in the basement). I can tell he's not ill...just upset with me, I think. I wonder how I can redeem myself to him because I miss him being all snuggly and drooly and happy.

He seemed better when I checked on him earlier...I brushed him and he was purring and he seemed happier when I petted him. I'll give him a few days and see if he's just having a mood swing or not...my girl cat out of nowhere began having them last year and she's alright, so who knows. And he was sitting on the stairs earlier, which he used to do before he got brave and went all the way up (for a while, was too frightened to do even this due to the new dog). Maybe he's just regressing or something, or the dog nipped him when I wasn't home and now he doesn't want to be up there.

I'll keep an eye on him, though. And I do know that cats tend to hide when they are ill, but this one's not so much hiding away totally since he knows I can easily reach him in his cat bed. Mostly I want to give him a little time because money is a major issue - I have no job and really no money I can spare, so unless it's a major emergency, it will be something that has to wait until I find a job.

For all I know, maybe I'm overreacting. As said, going to give him some time and see if he improves since the changes are maybe more subtle than I thought.

Maybe he's just getting old - he is 13, after all. Maybe going up the stairs is just becoming more difficult for him. I guess it just strikes me as odd that he was normal when I left two weeks ago and is acting slightly off when I get back.

The new dog has been here for over a year...my boy cat is more used to him but still spends more time in the basement than upstairs.

But I think this was just a false alarm as he was totally normal today...came upstairs several times (is actually up here now asleep on my bed), climbed all over me, wanted me to pet him. I think maybe I was just overreacting, possibly still getting back into a regular frame of mind following two weeks of major stress at school.

Trust me, I do keep an eye on all my cats for signs of changes in behavior and health. That's likely why I thought there might have been something wrong with my boy cat, but honestly, if I had to bet money (that I don't have) on it, I'd say he's fine and maybe just had a few days when he chose to be in the basement the whole time.

It's my girl cat I'm used to getting the mood swings from, not him. Maybe that's why I worried. I'll watch him for a few more days to be sure, but I really do think he's fine.