Had unprotected sex 2 days before my period, took a plan b within the hour, next day white discharge, and now clear watery thin kind of stretchy is it pregnancy or ovulation ?

It takes a few days for sperm to reach & fertilize an egg. It takes a few more for the egg to move to the uterus, attach and create any implantation discharge. While pregnancy has been documented from exposure at any point in the cycle, the chances in the cited story are unlikely. Ovulation would be an unlikely source of any discharge.

Low risk of preg. Conception occurs within day or so of the sex. It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully