Bleeding Low-Estrogen Birth Control

Hey guys! So I've taken "regular" birth control pills in the past and never experienced this harsh of a starting point. My doctor recommended low estrogen birth control because of other reasons when I chose to restart going on birth control after a few year hiatus.

I'm just starting my second pack and after a week of pills, I've started having the literal worst cramps of my life (I thought I had bad ones during my normal period LOL) followed by what I can only describe as a triple homicide down below.

Already taken a pregnancy test (negative) to rule it out outta paranoia, and I've read some people discussing "breakthrough bleeding", specifically with low estrogen birth control.

Just wondering if anyone out there can confirm/explain what breakthrough bleeding is and if this sounds similar to it. I also was wondering when too much bleeding is too much? (I don't mean filling up pads/tampons in 5 minutes with buckets, I know a lot is bad. I mean after 3-5 days of bleeding, should I get checked out?)

**I know the obvious thing to do is get off the internet and seek the advice of a medical professional but I also don't want to be in a financial hole for the doctor to tell me I'm overreacting lol. Thank you in advance guys!!!