Have 35 day cycle / 1st day of my last period was on 11.8.20 / i had un-protected sex on 11.18.20, and took a plan b within 2-3 hours / neg test on 12.4.20 and 12.9.20 / take another test?

Pregnant ?: Sex on 11/18/20 would be consistent with possible pregnancy, since sperm can remain viable for several days. Plan B is not a 100% protective method, but a negative test on 12/4 and 12/9 may be too early to detect a low level of HCG. Although the stated timing makes pregnancy unlikely, wait another week and obtain a serum HCG test, much more accurate with low levels of HCG.