"I'm not sure I was addicted, but when I had to stop running I really, really missed it. I fell into a mild depression."
I've been there too. Fought getting my new bionic hip for 10 years, until I could barely walk.
I have found that the elliptical, while not the same, does provide some of the running high. I love to flog 15k in the mountains, when not throwing the iron around.
The good news is with the new bionic hip, now a bit over 4 years old, started adding 1-2 days/week 5k jogs down by the ocean last fall. It puts a smile so big on my face it's funny