The breakup from your first love is never easy to get over. But despite the sad feelings you have now, you will, trust me, WILL get over her.
When my first girlfriend dumped me, I was a miserable wreck, and people told me exactly the same thing. I thought they were just saying that to try and console me because EeEEeEeEeEverybody always tells you that, but it actually does happen. Granted, it took me a DAMN LONG TIME (like, 2 years, which goes painfully slow if you spend every minute of the day pining for her)to properly get over her, but it does happen eventually.
Haha, I'm not saying it'll take that long for you though, I just think I'm not as strong-willed as some people.
Benjamin Disraeli said that "The magic of first love is our ignorance that it can never end." That's why first relationships are always hard to move on from when or if they end. But it also makes you emotionally stronger (obviously I mean once you have gotten OVER her) and more experienced. If you were to get dumped again by your next girlfriend (AND I'M NOT SAYING YOU WILL BE!), I'm sure it won't affect you as much.
So keep your chin up; I promise you your sadness will eventually dissipate. 🙂