Pregnancy weight

ᎻᎪYᏞᎬᏆᏩᎻ 🧜🏼‍♀️🦄
How do you ladies keep from gaining unnecessary weight during your pregnancy? I know you have to gain some but you don't have to gain so much. I lost a lot of weight a while back & I gained a lot of it back & now I'm afraid after I have my baby it will be all down hill from there. 
And how did you/do you plan on losing your baby weight & then some after you have your baby?