hi, I just thought I'd respond, so here goes.
I had an abortion 5 months ago, and felt just as you did. I'm 20 years old, an honors pre-med student, I just did what was right for me, and I won't lie to you, it was a very difficult decision for me. But I knew that my parents would react badly to either scenario. I was still living with them, they are paying for my schooling, I love my boyfriend very much but are not married or even engaged. If I had kept it, I would be alienated from my family. If they found out about the abortion, well I don't know how they would react, but definately they would not be supportive or understanding (well maybe my dad.)
Anyway, I felt just as you did the night before, and stayed up all night with my boyfriend discussing it, but in the end we both felt it was the best given our circumstances. I stayed up all night, but once I was there at the clinic, everything went so smoothly.
I thought from everything I had read that it would be a bumpy day, but to tell you the truth, it was so smooth (still hard though). Everyone at the clinic was kind, efficient, and I never felt rushed or disregarded in any way.
Hopefully your boyfriend goes with you, at least so you won't be alone. I know it was nice having someone there with me, even though i was in and out in only a little over 2 hours. Maybe you should try talking to him. My boyfriend never talks about it to me, and I wish I could talk to him sometimes. If you feel that you need that from yours, speak up, it won't hurt.
Feel free to pm me if you have any questions, and sorry for such a long post.