Hi Vivek,
Welcome to the forum.
As per your birth details provided here diamond doesn’t give the effects / harms as you have mentioned above. I would feel in your case the gemstone which you are wearing may not be natural or of good quality or you might have worn it on wrong finger or during wrong muhurtham or it might be possible that gemstone has absorbed negative energy.
GOD BLESS!!!
Srinivasa Temkar