migraine during my baby shower

Anyone else had a migraine during the third trimester? I get bad ones from eating eggs so I know to stay away and haven't gotten one in years. While opening presents at my baby shower I started to get aura and then my headache came
I took Tylenol and Benadryl and it kept my migraine from become severe. Sad because I was trying to not take any meds all pregnancy.  Wondering what could have caused it.. pregnancy hormones or maybe 100 degree heat in California today?
Anyone else suffer from migraines during their 3rd trimester? I mean legit migraines (auras, puking, etc), not just headaches.