Wierd problem

So our 18 month old is sick. Normally, when not sick we just say good night and lay him down for the night. He typically sleeps through. He has been waking up crying for a couple days. I can rock him back to sleep, but he freaks and wakes up when I put him in his crib. Now, I would love to just bring him into our bed so we can all just get some sleep, but he is so weird about it. Starts just crying and tossing around in our bed. He's happy to sleep with me on the couch (well on me) or in my arms. And he will sleep in my bed during nap time on occasion. Any ideas?