Hcg question? Help!

Andrea • Momma of 1 👧🏼 March 19- IVF-fresh transfer= miscarriage @8 weeks. July 19- 2nd IVF= 🌈👶🏼 Due 4/2!

So I spotted two night in a row. Had some cramping and thought I was miscarrying. My hcg levels have been rising the past two times I got checked. Well the third time I fully expected the nurse to say they dropped and that I was Miscarrying, but to our surprise they were high! 7000+. But weird thing is I took an at home pregnancy test the night before just to prepare myself and the line was so faint. How could that be?! Please give me some insight!! Any ideas!?