The former Dr Feelgood guitarist, 67, was given 10 months to live after being diagnosed with pancreatic cancer, but was given the all clear in April.
Johnson, who lives in Southend, says he now hopes to fulfil ambitions including playing with Bob Dylan.
"I'm finding it hard to mentally adjust to the idea that I can plan," he said.
Johnson underwent 11 hours of radical surgery at Addenbrooke's Hospital in Cambridge to take out the 3kg tumour.
The operation also involved removing his pancreas, parts of his stomach, spleen and small and large intestines.
He told BBC Essex: "You go in and see someone and he says three words that take about three seconds - you've got cancer.
"Bang, your universe has changed, absolutely and irrevocably."
After being given his terminal diagnosis, Johnson embarked on a farewell tour last year and recorded an album with The Who's Roger Daltrey.
But medics found he had a rare and curable form of the cancer when one of his doctor friends started to question why he was still feeling fairly well several months after he had been told he had less than a year to live.
Johnson said despite finding it tough to grasp the concept that he could think about the future, he does hope to tour again next year and release more music.
"I was very, very weak when I came out and slowly coming to terms with the idea that the end is not nigh - that I'm not facing the end," he said.
"Previously there wasn't a future so I was living in the moment.
"People would ask when I was going to die, have you fulfilled all your ambitions and I would have to say 'yes'.
"But perhaps one thing, I would love to play with Bob Dylan... because I worship him.
"I'm almost fit again and in the new year I will start playing again, doing gigs, and hopefully I'm going to sit down, scratch my head and write some songs and make some records.
"But it's all a bit vague."
The past four years have been fulfilling professionally. Julien Temple's 2009 documentary Oil City Confidential reminded people of Dr Feelgood's legacy and introduced a new audience to their music.
A stint as an actor in the hit US TV series Game of Thrones has also been a highlight for Johnson.
"I went over to Ireland to do the first part of filming and realised, 'man, this is a big, huge production," he said.
"There's one guy and his sole gig is to make sure the candles haven't burnt down.
"This is so different from rock 'n' roll - for one thing you get up much earlier in the morning."

Demonstrators sang Christmas carols and listened to speeches about immigrants and asylum seekers.
Weekly rallies by a group called Patriotic Europeans against the Islamisation of the West, or Pegida, began in October.
Several counter-demonstrations were being held on Monday.
Chancellor Angela Merkel and other senior politicians have spoken out against the Pegida rallies.
Wilko Johnson says he has found it "difficult" coming to terms with still being alive after being told he had terminal cancer.
[NEXT_CONCEPT]
A record 17,500 people have turned out for the latest "anti-Islamisation" rally in the German city of Dresden, according to police estimates.