Nah, bubs will be fine. Remember there is heaps of fluid surrounding the baby and his/her moving alot at 4am may have been in response to you tossing and turning, but not that you were hurting bubs IYKWIM? The bed will be hard for you and is probably making you feel a bit sore. Can you possibly take your mattress over and put on that bed? If you have another three weeks of it it would be worthwhile.