Mentally preparing for the worst....

Three positive hpt since last Wed with increasing darkness to line. HCG tested Mon at 675 and I need to retest next Mon to make sure its rising appropriately. I am about 5 weeks today. I am mentally preparing myself for the worst... I'm 34 1/2 years old with endometriosis. Took over a year to even ge to this point. This is my first pregnancy. Am I the only one that cant shake these negative feelings? It's all I think about all the time. Any advice on getting through these first weeks?