Yes, it is serious. He could have a blockage or go into stasis. You should take him to the vet ASAP!
"For the animal shall not be measured by man. In a world older than ours they move finished and complete, gifted with extensions of the senses we have lost or never attained, living by voices we shall never hear.They are not brethen, they are not underlings; they are other nations caught with ourselves in the net of life and time, fellow prisoners of the splendor and travail of the earth."
I changed his litter pan and well I guess he was pooping normally I.just didn't see him doing it. Scared me so much but since he is my first pet ever everything concerns me thank you for replying so fast.
He's a happy little bunny he was fine but since I hadn't seen him poop I freaked out but he was going regularly I just didn't see him but since the post he's been very happy and doing binkies all over the place