Condom didn't break, no ejaculation, took plan b, negative preg test after 3 weeks, also very stressed and anxiety, late period, could I be pregnant?

Unlikely. Your delayed period may be due to hormonal issues with plan B. If you do not get a period in 4-5 days, repeat the pregnancy test, use first morning urine and follow the instructions carefully. If you do not wish to be pregnant, use contraception all the time, every time. You may consider implanted contraceptive, or IUD. Practice safe sex. Get HPV vaccine.
Stress and anxiety. High levels of stress and anxiety are also associated with irregular menstruation, and may lead to delayed or missed periods. If these factors continue to be problematic it may be worth getting some skills training and education for managing anxiety/stress.

Related Questions

Late period after plan b, negative home. Preg. Test.! is it normal? When should I start to worry?

No worry needed. I do not understand the concept of worrying when all was done correctly except planning ahead for birth control. Plan b interrupts the female cycle for one to two cycles. The pregnancy test is negative. Next time remember planning to prevent unwanted pregnancy is a million times wiser than this worry. Read more...