Some grieving might help, but you need to do it in a good way. Losing ones hearing is just a too large concept to grieve about, so grieving would not really help much. Define for yourself what you really are sad about. It might be that you no longer can participate smoothly in a birthday party for a friend, since you cannot hear the conversation. Or it might be that you cannot hear your child on the phone. Ok, so grieve a specific thing. It is ok to be sad you cannot hear your child on the phone, but don't get caught up in grieving. Set a time limit, and say to yourself, this week (or whatever) I can cry and be grumpy and sad and angry (or whatever) but next week I will contact rehab to get a text phone or to get sign language classes for my child and me so that we can communicate easier later.
Of course we have the right to be sad when missing things we could do before. Remember that life is not worse just because you are deaf, life is just different. You are still the same person, so if people respected you before they should respect you now too. If you have friends who don't take the time communicate with you, teach them how they can make you feel included or look for other friends. Become friend with other deaf people, since having deaf friends will make it easier to be patient with hearing. Find out what is important in life for you and do many things you enjoy doing.
I agree with what was said earlier about psychologist's experience of deaf people. Consider going to someone who actually has experience of deafness.
You are not alone, and if you want to, there are so many great things you can do in life. Don't spend too much time grieving, because you might miss the opportunities available in life. You will need much patience and will power when dealing with hearing in order to get what you want from life. Remember most people are clueless about deafness, so you will need to be the one advocating for how too solve communication.
Good luck!