Got sent home

Was told to go to L&D at 4:30 this morning when my contractions were 5 min apart and I had my bloody show. When I first got there they did a cervical check and I was only 1 cm, 20% effaced. So they left me on the monitor to check baby's heart rate during contractions. Still contracting every 5 min and baby handled them well, so they unhooked me and said go walk. Walked for an hour, got tired and laid back down, was hooked back up. Baby still doing good. Next check showed only 2 cm and 25% effaced. So they sent me home! Said they may see me again tonight or in another week. I'm due tomorrow, so not early by any means. Problem is, I'm still contracting but now have no idea when to go in! I'm so scared to get sent home but can't imagine I haven't progressed at all at this point. I've taken a hot bath, bounced on my yoga ball, walked the mall, even napped. My back pain is getting worse so I will be jumping in the shower here shortly. Now I'm more stressed out than ever!