What caused late/missed period?

Obviously apart from pregnancy what else causes a late/missed period? I’m now a week late and tested 3/4 times and all test came out negative.

I have noticed the past few days I’m been having a lot more discharge then usual at times making me think I peed myself.

Also my hair has been falling out loads and my mood swings have been all over the place.

Anyone know what can cause this or even experienced the same things?

I’m just so confused rn🤷🏼‍♀️