Uplink port is used so there is no need for crossover cable, right? Does it use Auto-MDIX or is it an entirely different thing? if so what's the difference? please help :(
The term "uplink" can have several meanings depending on the context.
Most commonly in a networking context, it means a port that connects to another device that's "closer" to the data source. For example, on an access switch, the port that connects the switch to the distribution or core switch would be considered the uplink port.
However, in almost all cases, Auto-MDIX has nothing to do with it.
Since MDI-X was mentioned and in case that is the actual question: before Auto MDI-X became common (ca. 1999), switch and hub ports used to include a crossover in their ports (MDI-X) to allow clients and other devices with MDI ports to connect using straight, 1:1 cables.
Another option was to use a crossover cable between like ports (MDI-to-MDI or MDI-X-to-MDI-X). Today, the vast majority of twisted-pair ports supports Auto MDI-X which makes all that practically obsolete.