Can having sex delay your period?

I lost my virginity while on my period on the 13th of November and had sex only 5 other times after that day. The last time I had sex was the 8th of December. We used a condom each time and I'm 100% sure it didn't break. I missed my period in December but as I usually have irregular periods it is 31 days late but I can't be too sure because of that. I did a pregnancy test at the doctors on the 24th of December when I was 13 days late and it came out negative. Is it possible that loosing my virginity or having sex has delayed my period or even messed it up? I've been having bad cramps for a few days and I've been breaking out in pimples since around the 20th last month which I usually get before my period but it hasn't come.