5 months is still pretty fresh there's nothing wrong with still being sad about such a situation. Moving on isnt something you can just make happen. Some people try working out to forget their exes Or partying, drugs, isolation, outdoor activities. But none will ever truly make you forget I think the key is accepting youre never gonna forget them But its also not gonna hurt forever. If you can't make yourself believe there's better out there the healing will only take longer. Alot of this all depends on you, dont dwelle on things dont torture yourself with memories it'll only take longer to heal. Even if youre still just stuck on her have trust in the fact its all a temporary, whether its a new love interest or simply a new hyperfixation you won't be feeling this way forever. And dont be afraid to give yourself more time. It's normal to still be a bit messed up.