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 a day .. Could she be pregnant.. What is the causes of that abdominal pain.. Thank you