Hemorrhoids

I saw my doctor a week ago because I had seen a drop of bright red blood on my stool twice over the course of the last couple of weeks.  She used the anuscope and determined that I had what she called a large internal hemorrhoid.

I have started a high fiber diet and am following her instructions to the letter, and I've had no more bleeding.  The problem is I feel like there is constant pressure on my rectum now.  I'm starting to feel a little crazy and wonder if this part is just in my mind or is this part of the healing process.  How long does it take for the symptoms of a large hemorrhoid to go away?