No, you are not being unreasonable. Stick to your guns and get your price.
This ALWAYS happens in real estate.
They want you to take as little as possible so they can sell as quickly as possible and move on to the next one. They absolutely do not care a thing about you.
It is not worth it to them to spend several months working hard showing a house and taking phone calls for a few hundred or couple of thousand dollars more commission when they could take slightly less right away with minimal amount of effort.
If price is understandably important to you and you are not desperate to move, say no to any low offers, and if you have to, fire your agent, wait for the protection period to end - usually 30 to 90 days - and then do an FSBO.