Best exercise for pregnancy?

I’m so aware I’ve hardly exercised during this pregnancy. I’m 25 weeks, don’t want to overdo it but want to keep in shape and stay fit for after. My appetite has increased A LOT.

I used to go to the gym a few times a week before but in the first trimester I was too sick to keep it up. I promised myself I’d go back at 2nd trimester but I was too exhausted and my blood pressure was on the lower side too at some points. Now I’m almost in the 3rd trimester and really should do something!

Can anyone recommend some sort of exercise that I can do that won’t be too much for the baby but would be good for us?