FWB, not interested anymore?

My FWB and I took a bit of a break because I went away for three months this summer and now that I'm back in the city, we're planning to get together at some point. When we left off, he said to let him know when I'm in the city & free because he'd like to see me again but I've been so busy lately we haven't really talked about getting together at all except once. I asked him fi he was busy that night & he was until later but that was the time I was planning on being alseep at so we never got together. Then he said that it was fine & I should just let him know when I was free. I'm so confused. When we left off he seemed super keen to get together again but now it seems like not so much. Am I just being stupid or am I right to see something a little weird about it? Thanks.