This isn't me. But its a friend of mine asking for answers

My friend took a pregnancy test a few weeks ago and it came back positive. Well she went to the doctor and the first time they seen no baby just the sac so they assumed it to be too early, the second time she got the same answer, the third time still no baby. She went to a women's center last night due to bleeding. The bleeding has slowed down a lot but at no point was she soaking pads or anything. But her hcg levels were at 2200 well in 48 hours dropped to 1700. Doctor said her cervix is still closed but no one has seen baby and her levels are dropping. So our question is has anyones levels dropped and then come back up? Or has anyone ever went through this?