To forgive

I am struggling right now, trying to forgive someone that hurt me.  It keeps creeping back into my mind, and I keep trying to push it out.  I know that if I keep thinking about the things that were said, I am letting it take control.  So many people have stood up for me, with kind words, with advice, with scripture, reminding me to forgive, but it isn't instant, is it?  Sometimes, does it take some time to completely forgive?  I keep turning to God, but I feel like I am doing something wrong.   I feel like I should be able to forgive, and I want to forgive, but I can't push my hurt feelings aside yet.  They keep creeping up on me.  We are commanded to love our enemies, to forgive like God forgives.  I don't know how.  If I say that I have forgiven this person, but I still feel sad about what happened, have I really forgiven?  Is there a time limit on forgiveness?  Does it take time?  Or is that just the healing?  Is forgiveness the beginning of healing, or is it the result?  I don't know.  I am trying.