Weight gain

Oh no... I haven't been weighing myself through this pregnancy because I started out in a healthy BMI and midwife told me I was allowed to gain up to 17kg safely, I just checked today (I'm 21 weeks) and I've already gained 10!!!

Any suggestions on how to slow this down/mild excercises I can do? I dont eat much more than I use to but I definitely have become a lot less active