Are you talking about the Fort or the parks, rwc? (Not that I think it matters)
Mardi Gras occurs on Tuesday March 5 in 2019 (a holiday that floats) and just about the whole of Louisiana takes that week off (to vacation, to party, etc.) When I used to call on my customers in Louisiana, they were UNAVAILABLE then. And a lot of them go to WDW that week.
It's busy. Not as busy as Easter or spring break (mid-March) for many of the southern school systems.
To answer your question, basically, yes, it is more crowded/expensive than February but given that Disney cuts hours and staffs based on expected demand, it hardly never feels like "low crowd times" any more.
My two cents.
Bama Ed