Hello,
Since you have missed the birth control pills and had unprotected intercourse, chances of pregnancy are high. However if there is any unprotected intercourse then to confirm the status of pregnancy, I suggest you to test for pregnancy by a highly sensitive pregnancy test 10 days post ovulation with a sensitive ( 20 - 25 mIU ) pregnancy test. Also then I would suggest you to get your serum HCG levels estimated since this is more specific than urine for pregnancy tests.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
The 3 you had aren't enough to protect you from pregnancy. Even if you miss just one pill they usually suggest a perfect week before trying unprotected sex again. And on pill at the right time is enough- my sister missed her pill right before or the first real one after starting her sugar pills and got pregnant sometime that first week. The likelihood depends on ovulation times but it is possible for you to be pregnant.