If you're looking for a comforting reply, I'd come out and ask for it. I've found that's most helpful in communicating with my T over email (he only does text for scheduling) if I add something like, "I could just use a little reassurance right now" or "I could just use a few words of support." I'm more likely to get the sort of reply I'm looking for then. It also depends on how your T usually is with email/text replies--does he normally not reply at all? Or say something like "Let's talk in session?" Because then it could just leave you feeling worse.