Should I be worried?

Tiffany • William Dalas born September 18,2016.💙👶🏼 Teen Mom. 💕 YouTube: Dalas’ Mommy
I am 23 weeks , FTM and hardly not showing . I had an episode a couple of weeks ago where I didn't have any money to get food due to changing jobs and states. Is the reason I'm not showing because the baby doesn't have much weight yet? Or because I'm not gaining enough? I don't have another ultrasound till 30 weeks so I can't have an estimate on how much he's gained.