Take the time off as your doctor has advised you. Guilt shouldn't come into it. As you said, you can't cook your own meals, you're in constant pain and you need to be in a bed. I'm not sure why you'd feel guilty for not being able to work, that's why companies don't run at capacity and managers get paid to manage things when a team member is out.
Wait until you see the specialist and do what they recommend.
Not sure you'd be insured if you went back if you were signed off - certainly in Guernsey we aren't.
One of my colleagues, in the same position, was told that he wasn't allowed to return to work within his sick note for this reason. He also had to work from home beyond the note until such time he was mobile enough to be able to evacuate the building safely (both safely to himself and safely for other people by not blocking fire stairs etc).
When I broke my leg I was off for 6 weeks and then had a two week/half day phased return.
Take as much time off as the doctor tells you to! One thing you should check is how much company sick pay you get, ie. when you'll switch down from full pay to half, statutory, or whatever.