My (23f) fwb (28m) acted a bit strange when we last saw each other. Am I overthinking this, or is it worth bringing up?

I’ve been hooking up with this guy for a few months and it’s been great. The sex is amazing and we genuinely enjoy each other’s company. The last time we saw each other though, he seemed different. It started when I texted him early one week if he wanted to come over on Sunday (I’m always the one who booty calls, he’ll text me to send a meme or something). He usually replies fast, but that day, it took him a few hours. No biggie, it was during work hours, he was probably busy. Then on Sunday, he texts me an hour before we’re supposed to meet confirming if I still wanted him to come over. Interesting, he never does that, but I reply yes. He says he’ll be an hour late and I’m thinking he’s out with friends, especially since he was wearing a nice sweater and jeans instead of his usual sweats when he came over. But when I asked him what he’d been up to, he said he’d just been chilling at home. He’s about to travel soon and wants to save money and energy. I’m confused about why he was late and dressed up, but don’t mention it.

Now, this is when things start really feeling weird. I noticed that when we were talking, he was quieter/lower energy than what I’m used to, but in bed he was more romantic. Like his kisses felt more tender, things I did seemed to affect him more, and during sex, he suddenly hugged me tightly. But he also went limp at some point and couldn’t get it back up. He apologized and we spent the rest of the night cuddling and talking. A couple of things stood out to me in that conversation. He’s never been involved with someone over 2 years younger than him, so he asked me if I felt the age difference. I said no and when I asked him the question back, he said he usually didn’t because I’ve been working for a couple years, it be weird if I was still in school. He then wondered if anyone saw us together, if they’d think we were the same age or not. He also kept staring at some photos I have of me and my friends, asked me a couple questions about them. He’s seen these photos before but was never this interested.

When it started getting late, he said he should go. He said he preferred sleeping in his own bed, which is fair, but he’s always slept over. Before he left, he made a point to pick up the condom wrappers on the floor (“I can clean these up for you!”) and looked a bit sad when we said goodbye. I wondered if maybe he wasn’t interested in being fwb anymore, but he’s been texting me while traveling and we have plans to meet when he returns. Also, when we were cuddling and talking about his upcoming trip, he was like “let’s definitely see each other when I get back :)”. I’ll have to see how he is when I next see him but…he was being weird, right? I’m not sure if I should ask him about it, in case there’s something deeper going on whether it’s about our relationship or he’s going through something. But I also don’t know if it would be weird to ask, I’m not even sure how I would.

tldr; fwb was simultaneously more distant and passionate when we last saw each other, not sure if there’s a problem or if I should let it go