It's normal to lose friends over the years. Not everyone you're friends with is supposed to be your friend forever. People are brought into our lives for two reasons: to stay there permanently or to teach us a lesson. I think the worst break up is the friendship break up. We've all been there and it's tough, but I'm here to tell you that it's okay and that it's normal. That's the way life goes.
Falling outs. They happen and they suck, but it's for the best. You may not feel that way at the moment, but down the road you'll look back in time and see that it's a lesson learned. I'm sure many of us have had to go through these and it really takes a toll on you emotionally, but it only makes us stronger. Turn that negative into a positive.
Drifting apart. You were close friends, but as time goes on, you both get busy, have new set of friends, have new lives and suddenly you realize you don't talk to one another as much nor do you see each other. That's fair. Yes, some friendships are able to come back together, but most of the time they don't. The best thing about this is that since there's no bad blood, you remain cordial with one another and have nothing but fond memories to look back on.
Negative friendships. Separating yourself from negativity is the best solution. If you feel that a friendship isn't doing you any good, break it off. Cut ties. You need friends that lift you up and encourage you. Not "friends" who make fun of you, don't support you, and think you're beneath them.
Sometimes, friendships do not feel the same. You realize that you don't have that same bond that you used to have and that's okay. No harm done. You can't force it if it's not there. If you feel like your bond isn't the same and you still choose to hang out with them, at that point you're just using them. You're using their friendship to fill that void that's supposed to be there. Don't get sucked into that black hole.
You're "forced" friends. I've learned that sometimes the friends you think you have are only your friends because you see each other every day at school or work. The real test is to see if you both care to keep in touch with one another after school or work is over. If you never hang out, never speak on the phone, never communicate even on social media, you're probably not as close as you thought. I say "forced" friends because if you go to school or your job, you kind of have to go, which means you have to see everyone who is there, which means you have to talk to each other.
So, if you find that you're part of a friendship that's falling apart, think back! Look back to see what has happened. Better yet, make a pros and cons list. If your friendship doesn't bring you joy, say goodbye.