Confused

Any idea moms? I thought my last month of menstruation is June. Kaya every ultrasound ko, everytime I was asked about my last mens I answered June. I'm 7 months pregnant. But I suddenly realized that my last mens is May. ? I'm hesitant po kasi possible ba ma detect sa ultrasound yung months of menstruation or date lang? Nag alala po ako baka this feb ako manganak not on March. Based on my ultrasound March 10 ang due ko peru last mens ko is May. Dapat June. Naninigas napo tiyan ko peru no pain naman. Tapos parang may lalabas sa pem² ko tas masakit. Medyu masakit balakang ko. Pa help naman po