I'm 😢😢😢

Was told that I'm 7 weeks and 4 days because of my last period... But starting mild cramping on Friday night Saturday had brown spotting when I wipe and this morning had pink spotting... Went to the doctor and they say they see the sac but either I'm not 7 weeks or I'm about to miscarry... they say they can't see a heart beat.. my hcg level is 4000 so they say when I go for my first appointment on Thursday... If my levels haven't doubled then I'm going to lose the baby... And if I start cramping or heavy bleeding then come back in.... I'm stressing right now.. Anybody else dealing with this