How do I gain weight??

Ladies I need advice on how to gain weight! I used to have a more “slim thick” body type with thicker thighs and a bigger bum which I like a lot and personally think suits my body type the best. However, since I started university, due to stress and having drastically different eating and living habits, I somehow unintentionally lost around 10-12 pounds and absolutely hate how it looks. I’ve been spending the past month or so trying to gain my weight back but nothing is working! I don’t have time to go to the gym often or the money to be buying tons of food, but I’m looking for some general advice on how to put on some healthy weight. Help a girl out!💜