Confused advice maybe ??

I’m posting for a friend**

She is having strong pregnancy test and has for about a week she thinks she’s ABOUT 5 weeks but not fully sure . She had her blood drawn and it was only 13 they told her she was miscarrying because she had some bleeding she got her blood done two days later and it was 98 . Went to the hospital for a second opinion 2 days after last blood draw and hcg was 130+ (don’t know exact number just that it was 130 something ) also had an ultrasound and there was nothing on the screen ..

is she actually miscarrying ?? Her hcg is going up but it’s not doubling ?? So we’re confused on why it’s raising at all she was told a week ago that she miscarried and her hcg had gone from 13-130 something …