Help!! Really weird changes in my periods...

Hey guys,

So ever since I got my first period at 16 my period arrival, length, and symptoms have remained the same. More recently I lost weight and my relationship with food has changed (meaning I really REALLY don’t eat as much as I used to). Following this small amount of weight loss, I noticed a change in my periods .... a change for THE WORST. Now they come sooner and even at random times! I’m used to my period being consistently on-schedule. My periods usually would only come at the end of the month. Not only that but my period cramps have now become absolutely UNBEARABLE to the point where I can’t walk, and I literally ball my eyes out. Another thing I noticed is my uterus or at least my pelvic area is extremely tender to the touch during my period. Like aside from cramps the my uterus is always just in some sort of pain. And when I touch my lower belly I feel like I’m irritating my uterus as it feels tender, and full. Another thing is I usually have a fairly normal flow but now when I get my period, I can wear a pad all day for the first 2-3 days and barely any blood will be on it (which is extremely weird to me cause usually I have a heavy-medium flow) and then as my period continues then I start to bleed more but still not as much as I’m used to dealing with. Oh and one last thing! They don’t last 7 days anymore. My periods have only been lasting 5 recently. What could be the problem? I’m not sexually active. And I’m 19 years old.