I know it seems really really hard but I promise it DOES get better. The longer you go without messaging them, the longer they begin to think about you and what's going on in your life. I've been through this before and I know this time it'll take a little longer.
The dumpee tends to go through the initial "break-up" feelings as soon as it happens. Denial, grieve, anger, sadness, etc.
The dumper tends to be happy and relieved it ended at first, maybe feeling sadness and regret but only a little.. within time, (a couple of months down the line) especially if they aren't hearing from the dumpee at all, they tend to get nostalgic and think of all the good times and start wondering.
PLEASE remember NCR is not strictly for your ex to come back to you. It is for you to get over them Work on yourself.. if after a month or so you still want them back, you'll be a more confident version of yourself!