I'm in an awkward situation?

I'm really shy and self conscious. And I've never been with anyone, I find speaking to people hard at times even online. I joined a dating app and found someone I really like, we have been speaking for a few weeks.. I get the impression he doesn't like me, we speak on Snapchat and I always speak first but I don't say hi or anything I just send a general snap and if he replies I go from there (which he nearly always does) at first he was very flirty but it went off a bit but I wasn't very flirty back, so I tried being flirty the other day and he was a different bloke altogether, even asked me questions! Now I've found out he's extremely shy and finds it hard to get to know people which is what I'm like too so it's going to be hard work it seems. But I feel so annoying if I keep messaging but if I don't speak to him I miss him. I want to get to know him but I don't know how. I don't know whether to just go for it or not. Then he'll just stop a convo just like that.
It's awkward and I don't know what to do. See if someone messages me and I'm not interested I'd not be bothered speaking to them and it's like that's what he's doing but the way he flirts when he does suggests otherwise :( and he always replies.

Um help? What should I do. We have spoke a little everyday... because if he stops replying I'll send another snap so he sees that I'm there but maybe I should leave it a few days? But then what if he finds someone else?