That's a great gap of over 5 months for any test to be effective and be conclusive. You should not be worried an iota of it. The test was conclusive as per the standards mentioned on it.
CMIA or combo test that you had done is a fourth generation test so it detects both the antibodies
and p24 antigen quickly by Day 30. The antibodies that it can detect which would be appearing within three weeks after exposure. The 90% of antibodes would be formed in a month. So your test was done far beyond this standard time line.
So you should not unnecessarily panic.
The scenario of handjob causing HIV
is untested and inconclusive for HIV in all test scenarios.