Without knowing dates of your last and expected periods, and all dates of sexual contact during the cycle, it is difficult to form an opinion. Pull out sex works some of the time but is not very reliable. If you have some combination of weird cramps, headache, nausea, light headedness, unusual fatigue and emotions, breast and nip changes, appetite, smells, peeing more then a store-bought home pregnancy test is in order.
Take a real early result pregnancy test. Pulling out does nothing to help prevent pregnancy.