Lifted my 30lb niece today 31 weeks.

My niece fell today and I rushed and picked her up (natural reaction)she is roughly 30 pounds. I felt my tummy muscles tense as I lifted her so I immediately put her on the sofa. I have been achy and had a few seconds of cramps after. Will I have hurt baby or done something to my placenta? Totally freaking out with worry!!!!! Baby has been moving as usual and I dont have any blood or more pain.