Tingly breast sensation. Am I pregnant?

Hello, I'm currently on the combine birth control. I finished my packed on the 10th of January and then had my normal period on the 13th. I finished my period on the 17th and had  unprotected sex with my boyfriend for the next two days. I started my next birth control packet as normal on the 18th of January. However, two days after I started to have a tingly feeling in my breasts. That was yesterday on Saturday and today Sunday (20th and 21st of January) I was always taking my pill correctly and on time. Could i be pregnant or is it due to hormonal changes. It's been 5 days from the unprotected sex, I'm unsure if tingly sensation in breast could be a symptom of early pregnancy. I took a pregnancy test yesterday and it was negative. What should I do?