A grown man who discounts his wife's diagnosed medical conditions as being "all in your head?" This guy isn't just dumb, he's an active danger to your health and well-being. You don't mention if you have family with whom you're close -- if you do, get in touch, even if just by phone or email. Tell them what's going on. You'll need the support system, even if for just a few minutes a week. Also, contact your doctor about support groups for endrometriosis and fibromyalgia -- they'll be a good source of education for both of you. If you restrict yourself to only hearing your husband's negative opinions, pretty soon it will tear you down and you'll start to believe him. If he continues to be this unsupportive, you may want to look into marriage counselling, as well. It's hard, but this kind of thing needs to be dealt with early.
Regards,
Patricia