22 weeks pregnant no bump at all

Hi everyone I am going to be 22 weeks tomorrow and I feel like my belly just isn't growing. I am overweight. This is my first pregnancy but I am getting a little worried as to why I don't have an actual baby bump yet. My anatomy scan went well other than she was measuring 1 weeks behind. and I feel her flutters and light kicks in there sometimes but I don't know why I still don't have a bump. I have 3 other friends that work with me and they are all showing, and almost due around the same time but everyone keeps telling me I don't look pregnant and it's getting annoying! Is anyone else like this?