I am sorry to hear your news. It's very distressing to discover that you have to lose something so precious, even when it's for your long term health and wellbeing. The only consolation I can offer is that they clearly want to do this to protect you from the possibility of developing cancer. To know that cervical cancer has been prevented in you, albeit in a rather drastic way, is an amazing thing to not to have to worry about. That doesn't make it any less upsetting or distressing, I know, and it is a big loss to have to go through, but it's also great news that they've been able to offer you this at a stage before cancer has developed. It also means that the type of hysterectomy that you have won't be as extreme as it would be if you'd had a cancer diagnosis, which means quicker recovery and fewer long term side effects, which is good news.
As far as the op itself goes, it's best to discuss this with your gynaecologist. Every case is so unique that I think it depends on what your c-section was like. Also, even if this does mean you can't have a laparoscopy, it doesn't necessarily mean an open procedure. If you're just having a total hysterectomy, their first inclination should be to do it vaginally. Push them on this, as this is the way they are supposed to do total hysterectomies these days, and if they say they're not going to do it that way, you're entitled to get them to justify to you why not. A total hysterectomy carried out vaginally also means a quicker op, quicker recovery time and less chance of complications. As far as sickness goes - I know what you mean!! I am terrible with general anaesthetics - always violently sick with them, and this is NOT what you want with abdominal surgery, which can in itself make you feel queasy. Before your op, you will meet your anaesthetist. Lay it on thick about the sickness and about how much you do not want to be sick. Get anti-sickness drugs from him/her before you're put under, ask them to continue giving them to you while you're under (which they tend to these days anyway) and keep asking for more when you're on the ward. Some places only tend to give you them after you've been sick, which rather defeats the point in my opinion, so just make a nuisance of yourself and keep asking for them. Also, when you're being given pain relief, ask what it is. Morphine and in particular Tramadol, can make you feel (and be) very sick, so try and stay away from them if you possibly can - a vaginal procedure is meant to be less painful as well, so that should help you stay away from the Tramadol!
You're not going on; this is a very distressing time for you and it's not the news you want to hear, I know.