Should my girlfriend be angry to me because I was not able to date her because am broke?

My girlfriend got angry to me. I loved her and I do not knew what will I do. She' d been angry because i was not able to date her on valentines day. I am just a student and my parents do not fund my "extra relationshp". Should it be my fault if my girlfriend does not understand me. Im confused. Or, its her because she does not take into consideratons my situations,