My last (and first) online BF lasted about 2 weeks. He disappeared for 2 weeks without a word, then randomly came back. I told him to bugger off.

This one has lasted a bit longer. I found this girl who is in to many of the things I am. It was great for about 2 weeks.
Then she just suddenly went emotionally dead for a week.
Then she was back to normal for a week. My usually happy girl that I like, the one that likes to RP and hug and talk about things.
Anndddd now she's back to being emotionally dead again.

It's really starting to piss me off. I know woman have PMS and such... but I cant STAND her when she's dead like that. She oozes passive aggressiveness... weather she means to or not.

And I can always tell when it happens. She suddenly stops using emotes. Suddenly doesn't want me to call her. Gives single-word responses to things.

What I'm thinking about doing is just stop talking to her for maybe two or three days... mostly to get myself to calm down. What do you all think? Should I just give it up?

Well, since You don't fully seem to know what it actually is that is turning her that way perhaps You should talk to her about it when she's back to normal. If she's a good friend otherwise i think it wouldn't be fair neither to her nor to Yourself if You just stopped talk to her altogether. To take a break from her when she's not that keen to talk seems like a good idea though.

Have you tried to talk to her about it? Maybe something was going on in her life or who knows. I agree with Robin that you should talk to her when she's back to her old self and when you are feeling less frustration.

Maybe you should just take a step back for awhile and ask yourself why you're attracting the flaky. It's possible you're just looking in the wrong places for companionship.

It is a difficult one...how much do you want to turn them away...how much do you want to know why...if you never ask then you will never know. Be caring and considerate and hold out a branch.