Worried about my organs shutting down..

A little over a year ago at this time, I started to develop an eating disorder. It gradually progressed and I went from 164 lbs at 5'9 to where I am now - 112.

I was only eating 500 - 900 calories.

I tried a few different treatment programs, but that's a long-winded story and I realized recovery was something I had to do on my own.
And I am doing very well. I am still working my way up with eating, because it's more of a mental challenge than physical -- but I am eating 1,200 calories at the very least, and am within a 1,200 - 1,500 calorie range right now. Depending on the day and so forth. I still have some ways to go, but I am working on it and feeling better day by day!

The thing is, I am still underweight, my hair is still falling out, easy bruising, etc. etc. I know I will have to get to a healthy weight to stop all of these problems, but again, it's mentally challenging and is not an overnight thing. But I am working at it.
While I am underweight, however, there is still obviously going to be a strain on my body.. regardless if I am working at getting to a normal weight or not..

The past two days I have been very constipated and bloated. And it's being a real hindrance in my wanting to eat.
(My diary is open) I've been eating a LOT of fiber today, trying to see if that will help. But so far, nothing.

I read that this could be a sign of my organs beginning to shut down, and that has me very nervous.
Is that possible? I'm not sure of the severity and guess I could use a little insight! I'm also very hesitant to take anything with a laxative effect for obvious reasons.