You will.
It might take months. It could even take years. But I promise you that it does get better. You adjust to life without them.
Please take yourself on adventures. Go out with your friends, get into new hobbies, travel, live your life like each day is the last because I promise you, doing these things will draw the right people into your life. I know it's going to feel fake for awhile. It will be hard at first to smile, laugh, enjoy things, but keep at it. It will start to come naturally.
You might not realize this now, but you ARE in control. This person has no power over you. If you think that they do, that is YOUR mindset, and you can change it.
One day, one of two things will happen. Either you'll never hear from them again and be just fine with it, or they'll reach out to you again, and you'll feel nothing. Literally, absolutely nothing. Those "how are you"s and "I miss you"s that used to tug at your heartstrings, that made you believe in brand new beginnings which never actually came to be, will be empty words that you won't care to respond to.
Things get so much better once you fall in love with life itself. Exactly how it is. With all the unknown, the confusing, the frustrating, the boring, the change, the time alone, everything.
The only thing stopping you from living the best life possible is you. Not them. NOT THEM. They are a chapter, but they are not your entire story.
It gets better. I promise. We can't know when or how. But just wait. It's worth it.