I realize this is an old thread but a pet peeve of mine when when people talk about anything we like to do a lot as an "addiction". There are lots of addicts in my family and, trust me, liking to shop or exercise and doing it more than the average person doesn't qualify. To be an addiction, it has to impact your life negatively and you have to be out of control. (As was said above).
Anyway, you sound to me like someone who has found a new hobby and is very enthusiastic right now. That's normal with a new hobby. Eventually, it's not so new and shiny any more and you can be a bit more balanced about it. But right now you are in the "I'm in love with exercise" phase and you will probably be an annoyance to your friends talking about it all the time and wanting to spend all your time with it, just like when you have a new boyfriend.
P.S. If you think riding your bike for 30-90 min is a lot, you aren't hanging out with the right people. I'm going on a 4 hour bike ride tomorrow. And I'm not even close to being addicted - I work out less than almost anyone I know!