Not sure what's going on

so I just got my period on Saturday. I literally only need a thin panty liner for the whole day. this is also the first time I've gotten a period since August 9th. I've had an iud in for 2 years now and have been on a regular schedule for 2 years up until August. I feel like I'm getting fat and am starting to crave snacks. I've also been extremely emotional for the last 3 months. but every test I've taken has been negative. anyone have any idea what's going on?