Why isn't she texting back? (FIVE STARS - BEST ANSWER)?

[Chrome]

My ex and I talk a lot, (she is from a relationship two years ago).
Recently she had a medical problem and was sent home from school.
She missed today as well.

We haven't texted in a while even though we talk most days. Today I texted her when I got back and she hasn't responded. She's using twitter which she presumably goes to from her phone.

I don't understand it, I don't know whether she hates me or likes me.
Her twitter account blocked me, when I eventually asked her about it she said twitter sometimes randomly blocks people - I don't know whether she is telling the truth or not.

But we get on well, we talk with eachother and she tells me things that are important to her. I still love her, but I've kept this a secret. I don't think she really loves me though.

Even worse, she really loves her dogs and one of them died from cancer a year ago, she's still hurt by it and now her other dog has a tumour too. She was already suicidal and now things are even worse. I wondered if this was why she wasn't talking, but she's using twitter.

One more thing I know from what she posted on twitter, she's started her "woman time." I am assuming that means her period. I don't really know how a period affects a girl, is this maybe why she isn't texting back?

Here are my questions, please no trolling.
1. Why isn't she texting back?
2. How does she feel about me?
3. What should I do?
I do not feel she was getting too much attention from me. I don't constantly text her (this is the first time in six months), even when we were talking over twitter I never "smothered her".