Please Help My Betta!

That looks like a natural color change to me.  Some bettas change color like that very quickly.  I do not see anything "wrong" with your betta from those pics except she is a bit chunky.  Might be best to cut feeding down just a little bit.  I would not be surprised if she turns completely pale, turns all the way back dark or stays half and half.  That is the beauty of marble bettas.

I do agree with wildbetta she looks fine. But what do you have her on? Is that where you keep her?

Thanks for the responses!  I just put her in that cup for the sake of getting good pics.  She is in a 1 gallon tank which I change 1x a week. Before this happened i had gone 10 days so I'm afraid that may have made her sick.  She's also vertical in her tank with her mouth at the top and lethargic and not eating (I should have included all this info in my original message). All the water parameters are within normal limits (chlorine, nitrates, nitrites, etc). She's about a year old and has no history of illness.  I'm adding another pic so you can see how she's positioned vertically. 

Ok with a 1 gallon tank you need to be doing a 100% water change no less than every other day.  I strongly advise getting a bigger tank for her.  At the bare minimum 2.5 gallons.  Do you have a heater?  If not, you really need a thermometer to go inside the tank(not the stick on strip for outside the tank) and an adjustable heater to keep the temperature steady and stable.  The temp needs to be at least 78F with 82F being the best. 
 
What are you using to test the levels in the tank?  Strips or liquid test kit?  If it is the strips they are highly inaccurate.  

Colors also change a bit when they mature. She is after all, as you've said, a year old.

There is a weird looking patch on the first pic though, is that the end of the pectoral fins or just water droplets outside the cup?

Hi everyone, thanks for your help.  Her problem has worsened in that right at the line between her front colored part and her back gray part has become filmy and peeling and it's red and bleeding (not bad but definite) and I think she's losing use of her back half.  I finished a tx of sulfa and now I'm trying maracyn and maracyn2 concurrently to see if that will help.  She continues to sit vertically in her tank and breathe at the surface as much as possible. It does appear she's having trouble breathing.  I don't know what the heck happened to her. Trauma of some kind? It's kind of hard to see in these pics.  She doesn't live in the cup, I moved her there to do a water change but I don't think I'll do that again for a bit.  It exacerbated the problem and she was bleeding a little when I put her back.  Poor fish.   
 

Is the bleeding and peeling in one spot or all the way around?