I brewed a woodfordes Wherry kit on Wednesday and I thought it went well. It's a new kit with 2 sachets of yeast and I used both as per instructions. I got gravity of 1040 after mixing and am using immersion heater for heat. FV wrapped in insulation and blanket. Thursday was bubbling rapidly but today (Friday) it has stopped. Is this normal or have I done something wrong ? it's my 1st brew so I was meticulous about sterilizing everything beforehand. Any advice ?