I can so relate to what you are saying.
I myself suffered from Edometriosis, and had a full hysterectomy seven and a half years ago.
Just as you say, you felt great no more pain, I felt very relieved myself not having to suffer anymore.
Although that was very short lived, just a month later I went straight into the menopause. Having no ovaries I was advised this could happen.
I was put on HRT just after my operation, again just like you my life changed completely, especially the emotional side.
Things have begun to improve, I'd taken some time out from work, although two months ago I returned to work, and feel I'm beginning to struggle again.
At least now, I have the support of my husband and family more now that they understand what I'm going through.
Of course, I had to admit to them how much it was affecting my quality of life.
All I can add to this, is you are not alone, and just try and be patient.
Hopefully you will recover from this by getting through it as best you can.