What Causes Heavy Bleeding With Enlarged Uterus?

hi, i am 33 years old. i have bin having abnormal bleeding for 3 months now. last month i bled for 3 weeks. my Dr did blood work and that all came back normal. he also just did a pap test but we don't have the results from that yet. i had an ultra sound done on friday and they told me that my uterus was thick but i had just finished bleeding the wednesday before that and i had bled for 11 days very heavy. my dr called today and said he needs to see me right away cus he got the ultra sound results. i am nervouse because i also have hpv. what are the chances it is cancer? thanks, A