Hello Ashwini,
Low hCG levels may indicate a miscalculated date of conception, an ectopic
pregnancy, or a possible
miscarriage. However, a perfectly healthy pregnancy may have low hCG levels.
Now lets look at your case, your LMP shows that you were around 4weeks 1 day
amenorrhea when you took the + UPT and according to
beta hCG chart during pregnancy it shows that the normal range is from 5-426 mUI/ml. So saying if I am not mistaken, your beta hCG are perfectly normal and not low. TVS at 4wks a few days amenorrhea might not show any thing significant features, so do wait again a couple of days to weeks before you can get another scan.
My advise is worry less and be happy as I am sure that everything is fine and that you are going to deliver a bouncing baby. Please do not change your diet, just feed normally and avoid only toxic substances like
smoking, alcohol and get checked up for any pelvic or systemic infection that could compromise your pregnancy.
Wish you the best and hope you get a good time having your baby