I really want this to be yuri so my opinion might (will totally) swing that way. But I think she had tears when she told her fiance she was pregnant because she was regretting being pregnant.
Ever had a girlfriend/wife tell you "we're going to have a baby"? Tears galore, tears and add more tears. Now obviously this isn't always the case, depends on the women, how long she's known beforehand etc... But it's a pretty natural thing.
The thought of Ran inserted here might be a bit weird. I personally thought it was kind of shoehorned into the story for yuri's sake.
Although, many people I've encountered told me that when it comes to getting married and whatnot people often go through the whole "what if's" marriage blues where they think, what if I/We had done differently with XYZ partner. That's not really exclusive to relationships, there's a reason why we say "what if's" "shoulda coulda woulda".
Since I don't see how her mothers death (from earthquake) would relate to filling a void compared to marrying and having a child w/ a man instead of being with a woman for the rest of her life?
I'm not sure how the void analogy inserts itself. Maybe void needs to be filled with any strong emotions? Who knows.
I don't think it's her mother's death she wished for in particular. More like a " I wish a lot of people are suffering like I am suffering right now " kind of thought. Which an earthquake can totally do.
Continuing on with the void she feels the need to fill.
I think she just means that she can't be alone no matter what, she fears loneliness and if she can't get what she really want, she'll settle for ANYTHING. I don't think this was totally the case for many years, because she was fulfilled in her relationship with her ex-fiancé. But now that he's gone, she's still the same weak individual always in need of love and affection. Who knows what would of happened to her had she not met her friend back?
The progress she thought she had accomplished through studying and being more serious had been an illusion.
She's still the same old Keiko she always was. Which is normal, a lot can change in a person, but those deep insecurities will probably always be part of her.
As for the yuri elements we've had this chapter adding on to the rest. I can pretty much say she's bisexual, I'd go further and say she's pansexual. Ultimately she just wants someone, anyone, to never leave her.
Being sort of a loner, I can't totally relate to her. But I've seen people, especially women, who just can't feel fulfilled if they aren't in a relationship. I pity them really, not being able to satisfy yourself must be a pain.