Help please

In The bush next to my house lives a cat mom and her 5 kittens, so I also go feed them and play with them and they’re now about one month and a half , but the problem is that I’ve got too attached to them that I’m so scary and anxious about they’re mother leaving them after they’re grown and them leaving too . It gets to the point that I can’t stop thinking about it and my stomach hurts so bad.

Please give me your advises .