New to BC...pregnancy symptoms?

I know everyone is tired of the 'am I pregnant' posts...but oh well. This is a women's health app, so I'm gonna ask anyway (yes I'm going to test eventually, but there's a tww where I'd like advice).

Anyways...I just started birth control pills (microgestin fe to be exact) after my partner and I relied on pull out for three years. I started the pack the day after my period ended. As one could guess, we've had sex since then...at least once on what would have been my most fertile day. Well, here it is a week later...I have sore heavy breasts, ever so light spotting, and light cramps.

So my questions are:

Has anyone had a similar experience?

Could these just be birth control side effects?

Could these be pregnancy symptoms?

Has anyone here gotten pregnant on birth control pills?