Welcome to HC!
From the pics, the snake looks meaty enough to fast for a while. Try not to panic. The animal has been through a lot, and as Zane said: anacondas can be tricky.

BE PATIENT and try to stay calm. Here's a story for reference:
We have a Green Tree Python that is just over 3ft and has always been on the slim side: he FINALLY broke a 5 MONTH fast!! (20 weeks of trying different feeding tricks to get him to eat!!!)... Then one night my husband opened the terrarium, reached in with an F/T rat on the tongs and "bang", the snake snapped it up in a flash. He ate the second one offered as well and 10 days later, he ate two more.

Truth be told: regular feeding is not really "natural" for these animals. Their bodies were designed for feast and famine cycles. I think force-feeding in any form is really unnecessary in a healthy animal. A vet can check that he doesn't have mouth rot or parasites, etc. But we, as caretakers, have to learn to back off and relax. If he's healthy: when the time is right, he'll eat whatever he gets.

As Zane said: give the snake some better hiding places, then leave him alone completely. If the tank is in a high-traffic area of the house, try covering the glass with paper on a few sides. Decide on a day of the week for feeding and stick to it. Try heating up the F/T mouse or rat with a hairdryer or under a heat lamp. Feed in the dark. If he doesn't take it; don't pester him. Just try again 7 days later. In the time between, leave him alone as much as possible.

Make sure he has the right temperatures, and lots of fresh water. He could be going into a shed cycle too, in which case he probably won't want to eat until it's over.

Good luck!!

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Andrea

The snake is currently in my spare room, usually used for storage, so no one goes in there but me, once or twice a day to check on her.

I have force fed a snake once before although it was almost 20 years ago. It was a Ball python that had a calcium deposits in its stomach. She lived 10 years after that with my ex gfriend.

The vet will have to wait till after new years (the joys of living in the boonies.)