"The rash was gone but then I was struggling to move my hands. It was still in the back of my head about Lyme disease so I looked into it a bit more and I knew that these were the symptoms."
Lyme disease is an infection caused by the Borrelia burgdorfer bacteria, which is carried by parasitic ticks.
Symptoms such as fatigue and headaches, high temperature and joint pain can come within days or weeks of being bitten, the NHS says.
But rashes can take up to several months to appear.
Initial tests came back negative, but Dan's worsening symptoms meant he was given a six-week course of antibiotics.
"A couple of months later I was feeling a lot better," Dan said.
"Then I started to have one day a week where I felt a bit flat. From there I went even worse. I was bedbound. I didn't think I would get through and out the other side at one point.
"The worst part was that my head went to a big pile of mush. I was struggling to think or do anything. The exhaustion is like running a marathon every day."
A subsequent test taken privately finally picked up the infection, and another 26-week course of antibiotics was given.
Dan started to make a slow recovery, but said that this summer was the first since he contracted the illness that he had been able to function properly.
Despite knowing that he likely contracted the disease from a tick, Dan never saw one on his body and did not remove one from his skin.
"The worst thing and best thing about Lyme disease is that it doesn't kill you," he added.
"It just debilitates you. It strips you of who you are and what you are. It makes you a shell of who you were before.
"I know some awful stories. I have been really, really lucky."