people's clothes getting tighter - help??

I'm 11 weeks. I admit I suffer from majour body issues and have eating disorders so I know I'm over thinking things and mind is playing tricks on me BUT when did everyone notice their clothes getting tighter around their tummy? I know it's going to happen as the baby is growing etc but I wondered if I'm just putting weight on (scales saying only a pound or two) and I need to do more exercise or if it's just normal for me to be having to go up a clothes size already?