could i have endometriosis?

my older sister suspects I could have endometriosis because my period pains can be excessive. this past period, I was on the bathroom floor in fetal position waiting to puke but nothing happened. however, the past few periods, I've thrown up. which sucked because all those times, I was at work and had to leave early. (i hate being scheduled to work on my first period day for that reason) but overall, that's a new pattern for me. in the history of my period, I would feel nauseated but nothing would come of it. it would just be a wave I had to ride out. it's new for me to feel nauseated and actually throw up from it.

The thing is that my period pains and nausea only lasts the first day of my period. after that, it's just regular bleeding the rest of the week. I thought with endometriosis, the pain would last longer than just the first day. am I wrong?