You should never assume that you are meant to be alone because one single relationship (I’m guessing by your age that this one was your first) ends.
Most people who end up in loving relationships went through multiple relationships, all of which ended in one way or another for all sorts of different kinds of reasons.
Some ended out of mutual disinterst. Some people got dumped. Some people did the dumping. Some people loved the person, but then fell out of love, for a whole host of reaons. Some people fell in like, hoped that they would feel passion, but never did. Some people fell in love with an incorrect image of a person and then found out what the other person was truly like, and ended up not loving them after all. Some people fell in love and then the person had to leave or was taken away from them, like folks in the military. There are tons of reasons why relationships come to an end, but if we ever want to find happiness, we still have to make ourselves available for new relationships, and to make oursleves the best that we can be, to attract the best people for us.
Some people consciously get into relationships with people that they know are not good for them (such as people who are charming, but abusive or people that are married or involved with someone else, or people that they find to be extremely attractive, but they have little or nothing in common with, or people who they find attractive and that person has told them that there is no hope for a long term relationship).
All of the relationships that people go through (or endure) that end well or end badly teach us something about ourselves. Those bad or unhappily ended relationships show us what we really need and want in a relationship. The bad relationships also teach us what to look out for and what to avoid with the next person. All of these experiences, some good and some terrible, prepare us and guide us toward people that are more suitable for us, and hopefully in then end will be a good match.
I don’t believe that there is such a thing as soul mates, but I do believe that there are a lot of lids for a lot of pots and you have to put yourself in a position in which you can see the people that will be good matches for us and see the people that are likely to be bad choices. And by experiencing some of the bad with the good, we learn to tell the difference between good choices and bad choices. It’s all a learning process. Most people are not lucky enough to find their best match the first time around, although it does happen, but it’s pretty rare.
So give yourself some time (a limited time) to grieve over this particular relationship, but take away from it the tools that you need to find your next relationship. Don’t just jump into any old relationship, either, just because you are lonely. Figure out what it is that you want and don’t want in a relationship and try to seek out those types of people that will be most likely to make you happy.
Try not to be angry at the young woman who broke you heart. She’s actually doing you a favor (a painful favor, but a favor nonetheless) because if you stayed with her, it still wouldn’t have worked out in the end and you both would have been even more unhappy. Just be grateful for the joyful and good things that you shared, and never forget those things. Be thankful for the lessons that you have learned. It’s OK to be sad, and to miss her and to wish that things could have been better or different, but give yourself a limited time to feel bad. Don’t just retreat to your room and think that there’s never going to be anyone else in your life. If any of us Jellies had resorted to that, then no one would have ever gotten married or had kids or found any kind of happiness or love.
Love is a bumpy road, but it is a road that we all have to travel. The alternative is to stay in one place and never give yourself the opportunity for happiness.