Help! going through chemical and no clue what to expect.

Briana • Boy Girl Twins Born July 2018 at 32 Weeks after TTC since June 2015. MFI and APA syndrome. Had 4 IUIs and IVF fresh transfer prior to FET (2 early miscarriages from IUI and fresh transfer)
After 20 months and an <a href="https://glowing.com/glow-fertility-program">IUI</a>, I finally got my first ever BFP. It was early to test but I ended up in the ER so they had to test me before treating me and got the BFP then as well 2 days later when my Beta level improved. Retested my Beta level today )3 days later) and found out my numbers dropped and im experiencing a chemical pregnancy. My RE said I should expect the bleeding to start in the next couple days. I have no clue what to expect of the bleeding, pain, or anything else. I'm really upset by this and taking it pretty hard so any help would be really appreciated.