I'd try and not overthink it. Personally, I would reply much sooner than two days if I was interested and I was able to. I'm not one to play games and if I am interested, I'm interested and I don't play coy.

I should preface that with the fact that I've no experience with online dating and I'm in a long term relationship. But I've have several relationships in my life and if I'm interested, I've shown my feelings. If they weren't reciprocated or they were game-playing, I moved on.

Two days would personally make me wonder if they were interested. However, I would give them a benefit of the doubt. They may be cautious due to their own issues but still interested. They may have been traveling for work or very sick. Or maybe they are just casual that way. I'm not needy, but I'm not casual. There's a difference.

I think that time will tell but I wouldn't write them off based on this response time. Meanwhile, enjoy yourself whatever you do. xo

I hope this helps!