If me and my mate had sex 4 days before my cycle and sperm got inside of me and I still have not started my cycle is there a chance of pregnancy

Yes of course, that is what happens when you have sex. The time of the period has less to do, than the cycle of your fertile times. But now, you wait, for at least four more weeks to see if you have next months. If not take a HPT then.

Also of course there can be infections, STD and other issues to cause you to miss the period

Exactly... if you aren't TRYING to get pregnant... then use birth control... and even then, it can happen. Just a LOT less often than the panic and pray method.

I'm not sure, and try not to panic.

According to http://www.americanpregnancy.org/gettingpregnant/takingapregnancytest.html conception usually takes two weeks. However, I'm not going to pretend to be a doctor. If it makes you feel better, take a home pregnancy test. The same website recommends waiting until the first day of your missed cycle. Unfortunately, ovulation is the best time to get pregnant and that can be before and sometimes during your cycle. Either way, if you're missing your period right now, I don't think it is a sign that you are pregnant... but you could still be pregnant. You may need to wait another week or so to find out.

Best of luck. I hope everything works out for you.

I'm not sure, and try not to panic.

According to Taking a Pregnancy Test : American Pregnancy Association (http://www.americanpregnancy.org/gettingpregnant/takingapregnancytest.html) conception usually takes two weeks. However, I'm not going to pretend to be a doctor. If it makes you feel better, take a home pregnancy test. The same website recommends waiting until the first day of your missed cycle. Unfortunately, ovulation is the best time to get pregnant and that can be before and sometimes during your cycle. Either way, if you're missing your period right now, I don't think it is a sign that you are pregnant...but you could still be pregnant. You may need to wait another week or so to find out.

Best of luck. I hope everything works out for you.

If you are not actively tracking your cycle, there is absolutely no way to know that you didn't ovulate 4 days before your cycle starts. Period.

The ONLY way to determine whether the OP is pregnant is to wait for a missed period and take a test.

I will repeat to the OP what others have said: If you do not want to get pregnant, DO NOT HAVE SEX.