This just happened to me, and I need some serious advice.
Been there. It hurts like hell. As you don't give details, here are some general aspects that helped me:
First, understand that things change over time, and people change too. Relationships may last a lifetime... or not. And it's not your fault, so don't blame yourself.
Then - if it's over - all right, time to move on. Don't ask questions, don't beg, don't try to fix it - it's not gonna work. You may still have a casual relationship - salute, exchange of ordinary information - but that's it.
If you can, get a pet. Dog, or cat, or parrot. A rescue is even better. Their unconditional love and loyalty are pure bliss. To them, you deserve the best and you are perfect just the way you are. (I used to say that my parrot was way more joyful than my family when I got home). And you won't really have time to feel miserable when a tiny, sweet cuddle bug needs food or wants to play.
If you cannot get a pet, you can volunteer at a shelter. Or do any kind of voluntary work - you'll feel useful, and you'll meet new people.
Give yourself time. You will get over it, but not immediately. Avoid places or situations that may trigger you, or where you may meet that person. And don't look in the past anymore - you're not heading in that direction.
From my own personal experience (i am NOT an expert, someone smarter than me please correct me if I’m spouting bs), surround yourself with supportive friends and loving family members, branch out to make new friends, and/or work on loving yourself. I find that getting invested in something new, like a hobby or a tv show or something can really help get your mind off of the situation. Hope this helps lol
From experience; be sad for a bit, then realise that they were probably a toxic bitchington and you probably have other friends who genuinely care about you. Go out for lunch or bowling or something with them.
well, I've become more distant with my best friend too, we had a sort-of-fight, and I can confirm it hurts. Deeply.
Find support groups/friends to confide in, it helps! Write your feelings down, that always helps me, too. Drawing, too. Generally just venting on paper, and no one ever has to read it if you don't want them too. If there's any chance at all, you can try making up with your friend, too. Maybe write them a hand-written letter. If you did something wrong, swallow your pride and apologize, it will be easier when you do, but if it's a different situation, then...creature comforts! and find closeness in other friends! and therapy, I recommend therapy, it has helped me through so much, and there are options for low-income if you need it. I'm also, for the most part, here to talk, but I'm really terrible at checking notifs 😅
some tips that may help >>>
I read that you have a cat named ollie! maybe hang out with them, take a few cute pictures :))
listen to your favorite songs! this one really helped me while I was going through something like this. the songs don't need to be happy, they can be anything that makes you feel better :D