On bcps but had sex w/o a condom so i took plan b 1 hr after just in case. 8 hrs after plan b very heavy clear/white stretchy discharge? is it semen?

Possibly: If you were on Birth Control (BC) pills and used them consistently you would not need to use Plan B. But if you were not using BC pill every day then using Plan B was the right thing to do. But I would recommend you use condoms for protection against STD's. The clear discharge could be semen, but if it is an STD due to lack of comdom use I would advise you see your physician.