Absence of poo on birth control?

I've heard that high levels of estrogen can mess with your bowels.

I'm on my 2nd week of taking the pill, and over the past couple of days, I've noticed that my bowel movement isn't that great. I've gone #2 multiple time in the 2 weeks, obviously, but now I'm getting worried.

I've tried eating loads of different foods to see if anything happens, and literally NOTHING has changed.

I feel like I need to go #2, so when I try to, I have to try REALLY hard and I'm only able to pass a little bit.

Could this be related to my birth control and is it something I need to be worried about?