Definitely stop worrying.
Your charts look good, clearly defined ovulation and a decent LP length. What you have to understand is the immense amount of impact artificial hormones has on one's body. It regulated everything for you, endometrial lining, start and stop of cycles, ovulation repression, etc. I'm guessing the reason your periods are so short/light now is because your body is readjusting and learning to build up that endometrial layer on its own again.
I wouldn't be surprised if it took you 6 - 8 cycles off BCP before you start to have a "normal-for-you" cycle. NO WORRYING!