Weight gain?

During my first pregnancy I was in the gym everyday due to working away and being bored also all I ever ate it fruit and veg I don't know why and I didn't gain any weight untill 5/6months. With this second pregnancy I'm only 17 weeks and gained a stone and 3lbs (I'm not bothered how much weight I gain) but I'm just wondering if this is normal at only 17 weeks as I know we gain the most in our. 3rd trimester. My diet is so so bad and I'm jot that active I don't work and I'm not very active I do the house work everyday and go the shops but that's it but I have so. Many take aways and cake and chocolate. Is it because of my diet or can this weight gain be classed as normal?z