Minecraft Realms - Error 6003 Upload Limit Reached

I've uploaded several maps to Realms, trying to find the one I like, and all of the sudden, after about 4 or 5 uploads, it tells me I've reached my upload limit. I've read that other people said that the map is too large for Realms, but when I try a map that worked previously, it gives the same error. Please Help!