It depend on your normal. Stress has a lot of factors when it comes to the human body sometimes it can even make you late or not have one at all or it could make it worse I am a high stressed person and I have had it all kinds of ways it just depends on your cycle and how stressed you are also you may want to take a pregnancy test in two weeks just to be on the safe side you can have a light period when you are pregnant for the first couple months
No it makes it worse
Possibly, can make it worse, or even make it stop for a while. Make sure you are not pregnant too.
Yes, stress can not only affect that, but other things of your body as well. It can even delay your period, I hate it when it does it to mine.