Every once in a while, I end up feeling extraordinarily lonely. I end up in a fit of depression for a few days or even a week. Right now I hate myself because I hate myself. Does this dumb sort of thing happen to anyone else? Any tips for getting through it?

It happens to everyone. We all have our ups and downs, but if you feel yours are getting out of hand, the best thing to do is speak with a professional.
Beyond that? A little bit of positive thinking does a world of good. People with depression spend a lot of time doing nothing and procrastinating, and finding something to occupy yourself with can be quite helpful in dampening those bad moods.
Sorry I don't have much else to offer.

That happens often to me, but I don't find that really depressing. I end up thinking of the world rather than myself.

Like >>2 said, you should busy yourself. There isn't really any other solution, you just have to get enough things not to keep you from depression.

>>1 Happens to me every now and then. Aside from maybe taking antidepressants or talking to a therapist or something, there's not really much you can do but wait it out and go through your day or week like normal. You'll still feel eh but there's not much you can do because more often than not, the things that make us sad and go through these periods of depression are not really fixable or if they are, it's very very difficult to fix it.

It happens to me right now. And like you, I really hate myself too. I'm currently trying to do meditation, or if you are a busy person, a relaxation. Just relax and close your eyes, take a deep breath thrice, and then focus your mind to your breath. Daily relaxation somewhat helped me, just 10-15 minutes a day is enough. And I agree with >>4, there's nothing you can do but wait it out or try a little harder.

(ps: there's an anime called Colorful, my friend said it really helps anyone who's in a state of depression, go try to watch it if you want :))

>>1 If there would be club for this sort of thing, I would invite you. I guess, there a lot of more people who have the same feeling.

Depression are really hard to overcome. If you can't do it alone there is nothing wrong with looking for help!
Just talking to somebody whom you can trust will help a lot!
Even if this person doesn't know what you're talking about, as long as everything is taken serisously what you say, it should be okay.
If you don't have such a person near you, you can also write down your thoughts.

Self-hatred is...nasty..
Self-destruction is a very strong emotion. I know it, too.
It's even influencing relationships to other people, friends and family.
But self-hatred often has a certain source. maybe rage that is not allowed to express itself or blaming..

I can only say, what I'm doing in such a case where I hate myself very much...
I'm writing down, what's bugging me. I try to analyse why I hate myself - what is my inner critique? When I try to find a solution for the certain problem I wrote down.

To break the cycle of self-hatred, you need to face yourself! - serisously and earnestly! Don't lie to yourself. Be honest.
And Say "Yes" to yourself. If you look around you, there are probably a lot of people who think you are very precious!
that's why YOU should think this way about yourself as well! :)