Braxton hicks

Laura
What do Braxton hicks contractions feel like? 
Yesterday I was admitted to the hospital for not feeling the baby move so Much and for having a persistent crampy feeling... I was monitored and they saw small irregular contractions on the monitor...  They said I was dehydrated and I was given 3 bags of iv fluids. They monitored me for 8 hours and then o was discharged and sent to my ob this morning. He said not to be surprised if it happens again be uses it might have been Braxton hicks contractions since I'm 27.5 weeks. How can I tell the difference better Bhc and dehydration cramps?