Don't get too caught up on this, man. You can receive a reply in 5 minutes, 5 hours, or even 5 days. Leave the profile alone, go for a walk, and then come back fresh. Your posts tell me you're wasting too much mental energy on this, and your tone makes me think you're already assuming failure.
Just chill out, relax. Let's say some random girl you've never met suddenly stops replying to you. Big deal. Seriously, its nothing in the grande scheme of things. Some time soon I'll send you a PM with my own experiences, some of them are just ridiculous. Hopefully it'll give you some perspective of what some of us have been through with online dating. You'll see that its very common and you're not the only one (even though it may feel like it at times!).