I am 2 months late on my period.. I took a home pregnancy test a week ago and it was negative.. how much longer should I wait to take another one if I don't start my period?.

If your two months past it your not pregnant... just go to the doctor and have a blood test done. That's the only real way to know.

Yeah as lala said
Or they can do a Urine test as well

My GF done:
Doctors urine test
And a home ( clearblue ) test
When we found from the clear blue she was pregnant we were so exited
And then the confirmation from the doctors was the icing on the cake!

So try nipin to your doctors:) they will help
Take care..

I wish you all the best!