Hey, I know it seems tough right now. How could it not? It's been nine months, and you're probably telling yourself that you're being stupid, that you need to get over your ex, that dwelling doesn't do any good. But while dwelling isn't good, it's also important to remember that everyone heals differently, and that it takes time. And that's okay. You don't need to be 100% fixed at a certain date after a breakup. Hell, depression can even occur because of a breakup, and that's normal. It's okay to not have this resolved quite yet. The important thing is that you get it resolved fully, not that you do it quickly.
Keep moving forward. You have to remind yourself of the good things in life that aren't related to your ex. Find new hobbies and start new goals, like learning to play an instrument, getting a new pet, starting a new book series, beating a video game, learning a new language, trying unfamiliar restaurants in or around your area, etc. Remember to wait until you feel comfortable to start up a new romantic relationship. The important thing about relationships is not to need one to be happy; you find your own personal, independent happiness and find someone who you are willing to exchange happiness with.
If you're getting worried, don't be ashamed to see a counselor or a therapist. It's not strange or weird to be so broken up over a breakup. It's a major life change, and no matter how small or even how positive, any source of stress can negatively impact the body.
Good luck!