Should people be going to emergency room for non emergencies

Someone made a comment that it was bad I was going to the er for non emergencies

And that I’m taking away valuable resources that could be used for other people

I’m 16 weeks pregnant and was diagnosed with placenta previa so my pregnancy is high risk because I’m constantly bleeding that I get very dehydrated and weak

So my obgyn tells me if her office is closed an I feel I need to go in for me to go

Only thing they give me at the hospital is fluids and do ultrasounds and monitor me

But should people like myself not go to the er for this

Or people who are sick not use the er and just wait till their doctor office is open ?