Forget th hysterectomy - they will not give you one for many years yet. Besides which is does nothing at all to help the battle with endo. Endo can be everywhere but the uterus so not much benefit to having it reoved other than to stop your menstrual period and there are other not so dramatic ways to do that.
You depression is 100% down to the zoladex - it is a very common side effect and I would urge you to either contact your GP about anti-depressants or better still come off the zoladex. It is not curing you infact it is hiding the endo - making it dormant for the time being and much much harder to find when you do have your next surgery.
So really the best thing for you is to stop the zoladex and not have another before the op.
it may be something you want to try again later on. Once you are better prepared for it and its side effects. Stopping the drug now - does not mean the immediate return of the endo pain - it can take a few months for the ocaries to wake up and that interim period is free of th menopause side effects and free of endo pain till it wakes up, so quitting seems the most sensible option by far.
Seeing as it does nothing to cure your endo and is only given to improve th quality of your daily life for a short time - if the side effects have made the quality of your life worse then no reason at all to remain on it.
A decent endo surgeon will not laser back the endo - they will excise it or cut it out that way they get deeper endo removed. After that its a case of taking steps to stop new endo spreading from the uterus by taking steps to stop the frequency of your periods.
I hav stage 4 endo - it was everywhere but in 30 years it had stil not blocked my tubes - just because you have endo everywhere does not necessarily mean your tubes will get blocked by any means. And even if one side does the other may remain a tube for quite some time, and even if both eventually do get blocked there is IVF.
Given your age you have a heck of a lot of options still ahead of you before you remotely consider a hysterectomy.
The primary focus should be to get an endo expert surgeon working inside you to remove as much of the endo as they possibly can. Not a bog standard fertility gynaecologist but a proper experienced endo surgeon who will do a decent job.
This should relieve a lot of the endo pain for quite a lot longer than simple laser attacks on endo will do.
Recovery does take a bit longer to get through if you have a proper job done on the endo, but it should then give you back a much improved quality of life whereby you can face up to a pregnancy and more importantly - the coping with child rearing while you do have to battle endo, because it is no picnic having a chronic illness and trying to run a household and care for youngsters.
Any surgeon which promotes hysterectomy for endo in anyone so young needs to be given a very wide berth. They clearly do not understand what endo is all about. You much discuss with your GP asking for a referal to an endo specialist surgeon. You owe it to yourself to get the best surgeon you can find.
There is a list of accredited UK endo centres and provisional centres on the following website:
Get yourself referred to one of these locations to make sure that endo is properly removed and you won't need to have any hysterectomy any time soon.