If your goldfishes tank would support it, you need to obtain a couple more Goldfish of a size slightly smaller than the female you have. You need to get something which will serve as a spawning matt. Perhaps a shredded white washcloth doubly rinsed would work. The spawning matt is just a soft entanglement for them to rush into and lay her eggs in.

Second choice: Gently, (more gently than you would affectionately tweak a childs nose)- you can massage her sides, from behind her gill covers and downward to back near her vent - to expel eggs. If she doesn't naturally, (as above in choice one), or by massage, expel those eggs they could try to be resorbed which is not always successsful.
If she is impacted you will rupture the ovaries which provides a few days of relief before they die. If you get blood with the massage you have ruptured the ovaries.

Third choice: Leave her alone. Even though it never happens in Nature that a female would have to expel her eggs without a spawning mat (live plants) or a male, she *might* be able to do it on her own and she might live. The worst case would be if you intervened, and then worried you'd done something wrong in the case that she went ahead and died. So you have to decide.

If it were my kids Goldfish I would lift her out of the water and gently massage her for no more than eight to ten seconds every day for three days.

Perhaps she is not eating and depressed because we know that her eggs are infertile and are decaying, which is dragging down her water quality by causing accumulation of ammonia, declining pH and consumption of dissolved oxygen. If the water looks less than perfect, a major water change with dechlorinator is in order. Water testing on a regular basis through this crisis will prevent a secondary stressor from pushing her over the brink.