Wondering

I'm 27 years old and my girlfriend is 26 years old. My girlfriend and I had an outercourse with her vagina an my penis rubbed (23/12/19) and my penis never inserted to her vagina and then it followed by a normal menstrual bleeding on 30/12 which was a bit early(the first and the last time we had a sexual activity) . However in the February of her menstruation was late for more than  a week  and we took upt on 6/2 and a negative test was shown and then her menstruation and cramp appeared on 7/2 but on 22/2 she had right breast pain for only one day. In the 3rd month menstruation comes exactly 10/3 along with the pms  4 days prior . But on April 1st she had abdominal pain in the lower right side and it made ger vagina feels tingling .. Could she be pregnant.. What is the causes of that abdominal pain.. Thank you