No a sensitive test would likely be able to tell you already. There are rare cases that women don't test positive on a home test till weeks after a missed period because of how their body metabolizes the HCG hormone. Most tests are 99% accurate the day after your missed period. A blood test would tell you for sure though.
No just wait til Monday but a blood test want show up now
Yes its too soon to test... test again in a few weeks. 2 weeks after period you can do a blood test, 4 weeks after period you can take a test at home