I am approximately 5 weeks. my hcg test came back at a 148. should i be concerned?

No, Don't worry: HCG levels vary widely. At 5 weeks, normal range hCG = 18 – 7,340 mIU/ml. hCG levels tend to double every 2-3 days during early pregnancy so monitoring change in hCG level is more meaningful than a one time measurement. Caution must be used in making too much of hCG numbers. A normal pregnancy may have low hCG levels and result in a perfectly healthy baby.