Still fitting in my jeans at 17 weeks?

So i havent worn jeans in like 2-3 months because well quarantine and work from home. I live in leggings.

Tonight I thought I would try my pre pregnancy jeans and I still can button them! I was so surprised, Ive been feeling considerably bigger. I mean my jeans are size 4! I did gain about 5-6lbs so stange!

Is it normal? Is something wrong with me?