Weird pregnancy cravings? or smells? HELP!?

Hi im 31 weeks pregnant and for the last 3 weeks, ive been like craving the smell of a hoovered carpet, i even wake in the middle of the night, and want to hoover just for the smell, i feel like eating carpet, i heard this could be a sign of low iron, but my blood test has come back fine, i could just hoover all the time, people have said oh your nesting, because i do feel like cleaning all the time, but its really annoying me the way i just want to hoover all the time! like constant, i just crave the smell of carpet, what can i do?!!