Uy anak, I'm so glad you called your OB right away, you did the right thing! Please go to the hospital na now para ma-admit ka and ma-monitor both you and baby properly, especially since you're already dehydrated at 36 weeks. The doctors need to check what's going on and make sure baby is safe while they care for you.
A few of us mums have gone through scary moments like this ganitong weeks, at ang best thing talaga is being under medical watch, it gives you peace of mind, honestly. You're doing everything right by reaching out to your doc and following their advice. Mama, the baby's heartbeat is good which is a very positive sign, so trust your OB team now, okay? Malakas ka, kaya mo yan. Keep us posted when you can, and sending you strength.