So I'm 24 weeks and for some reason today my belly is super tight and tender. Is this still from…

So I'm 24 weeks and for some reason today my belly is super tight and tender. Is this still from expanding do you think? I was super lazy all weekend and today I'm back to work which I'm on my feet a lot and doing some light lifting, but it's the first time it's happened and since this is my first I'm nervous about everything!!!