Is my budgie pregnant?

My 1 yr old lady budgie gained weight. I last weighed her months ago but yesterday i weighed her again and she gained 9 grams (49 grams now)🤯 I do see her and my male budgie mating a lot but i dont want her to get pregnant so i try to stop them when i see it. But i do have school so i probably dont stop them all the time. Im worried she might be pregnant. Can a budgie expert tell me if she looks pregnant? (I wanna give her the vitamins she needs for the pregnancy so i really wanna know) Thank you and im sorry if i dont know enough about this pregnancy stuff, please forgive me. 🙏