After lumbar laminectomy, no fusion, how much exercise can I do?

after i have my lumbar open laminectomy jan 28 no fusion how much exercise can i do. Can i go go on my stationary bike takes walks drive my car go to pt as i am a active person and dont want to sit on couch watching tv and my legs get weak for long time . how active were you after this surgery. Note After i had cervical laminectomys had pt 2 weeks after and i drove my car right after so why should a back be any different cervical surgery. How fast did you recovery from this in normal activities .