Fresh wounds always hurt the worst. This sounds like it just happened. You are obviously going to need time to emotionally move on from a failed relationship.
My advice is to distract your brain from the event in the short term. Play with your pets, go see a movie, hang out with your friends, eat some ice cream, focus on your creative hobbies. When this sort of thing happened to me when I was younger, I would flip it around and use my newfound single status as a positive - I can enjoy the foods and activities that I knew my ex-partner didn't like, I didn't have to plan my schedule around making time to see them and include them in stuff, and I just generally enjoyed the liberating feeling of being single, even though it still hurt to lose someone so close that I had been so attached to. By the time I started to feel like the feeling of being single was losing it's appeal, I was emotionally ready to move on and meet new people.
In short, just give it more time. Distract your brain. In time, this too will pass.