No. Pregnancy doesn't automatically make itself known (well, aside from the possibly missing periods!). Rather, it develops slowly.
For example, the baby bump wouldn't begin to be visible on most people until the fourth month of pregnancy.
Other possible signs of pregnancy can also be signs of PMS, which makes it even trickier to know if you could be pregnant.
A good rule of thumb is to wait for your period. If it comes, great. Work out a better method of birth control for next time and continue with your life.
If your period doesn't come, get a home pregnancy test. The sooner you know if you are pregnant, the sooner you can make an informed choice about your options.