Pressure/dull pain in the lower abdomen

I am 15 weeks pregnant and quite showing for 1st pregnancy. Every night, I tried my best to sleep on my side coz sooner or later, I will really need to do it regularly. But every middle of the night, I always wale up sleeping on my stomach and would feel pressure/ pain in my lower abdomen.

Is my baby okay? It happened several times already. I decided to purchase a pregnancy pillow to make sure this one will not happen.

Thank you!