Keep getting negative but feel pregnant

Nicole
I am 23 as me and my fiance haven't been trying for long I am worried because my sister had a very hard time with her first and her second child the doctor said was a miracle and she had cancer through out the pregnancy. When she finally gave birth they did a hysterectomy. I have very irregular periods and have cysts, I am now 6 weeks since my last period which is unusually late for me and me and my fiance have been trying nearly every day. I have been peeing on a stick almost everyday as well and no luck, last week I went for a blood hcg and got a <1 I went again 8 days later and got a <5 which is higher hcg but not pregnant. I feel pregnant o as well had an ultrasound and they only saw many follicles in both ovaries.. so confused so stressed if anyone has any input would be great!!!!