My LMP was 28th March

HPT was feeble +ve,, twice taken with a gap of 2 days n both very feeble,,

1st hCG - 21600
2nd hCG - 5900

Scan report says G-Sac seen but no fetus signs so far, needs follow up after 10 days

M tensed,, I donno if m pregnant or not,,

When were the hcg levels drawn? Certainly numbers dropping is not usually a good sign. When was the scan done? If it was very early, they may not have been able to see much just yet.
Unfortunately you will have to wait until they do a repeat scan and likely another blood draw.

1st hCG on 9th May
2nd hCG on 11th May
Scan on 14th May

The radiologist said it'l take at least 10 days more to get the fetus reading, i.e. if it's there,,

M going to the doc 2moro but m feeling very scared,,

My problem is that I lost my 6 months old baby gal in nov and then my periods went irregular,, I conceived again and it was in the tube,, this time I conceived but its feeble and hCG is dropping,,

M not bleeding either that I can call it miscarriage,, everything is going to ma head,, m feeling scared... a lot,,

Your doctor may or may not decide to check hcg levels again to determine if they are slow to rise, holding steady, or if they are continuing to drop.
Since you had one ectopic, it does increase the possibility that you may have another. That may account for the change in hcg levels.
Maybe it's ectopic again, maybe there was a very early loss, maybe the numbers were skewed and a pregnancy will still be picked up.
You'll really need to see what the results are on the next scan.
Fingers crossed...

Thanks you...