Could I still be pregnant?

As of today, I have been 70 days without a period. Saturday makes five weeks that I am late. I took several home pregnancy tests and all were negative. I had blood work done as well, and that came back negative, too.

My symptoms:
-late period
-cramps in my lower abdomen (feels as if I am going to start "right now" sometimes)
-extreme fatigue (all I want to do is sleep..all day long!)
-nausea after eating and throughout the day
-urinate more frequent than usual
-headaches
-boobs became sore within the last week

What concerns me most is that someone in my family had both a negative urine and blood test, but she later found out that she was pregnant. My aunt was treated for stomach cancer but the doctors discovered she was actually just pregnant moments after performing an ultrasound to see where the cancer cells were located. Before knowing she was pregnant, she began taking medication for cancer treatment which resulted in my cousin being born with severe stomach problems.

I don't drink or smoke, and I don't really do anything that would harm my child if I am pregnant. I did have unprotected sex more than once, so the chances are definitely increased because of that. Is there anything else that could cause my period to be THIS late when it is usually pretty normal? One more thing, I also went to the doctor and was treated for a urinary tract infection. Weird thing is, I urinated in a styrofoam cup and the doctor said there was something floating around inside my pee. I may not be a doctor, but it's pretty obvious that what was floating around (because it white and kind of big like pieces of the foam) was pieces of the cup that had come deattached. Urine is usually warm, so I figured that was what caused the pieces to rise from the bottom and float on the top. Anyways, he treated me for this when the ONLY symptom I had would be stomach pains and nausea. However, I don't burn or hurt when I use the bathroom. There is no blood in my urine nor does it smell strong or is dark/bright yellow. I drink lots of water which makes it clear for the most part, but yet he treated me for a uti. I'm so confused!

[Dr. Kokil Mathur]

Hi!
Since you have a strong family history of pregnancy with negative tests, and you are now 70 days without periods, I suggest you get an ultrasound done. This will confirm pregnancy. Also it will rule out other causes of missed periods like polycystic ovary. If these are ruled out, then you have to rule out other causes of secondary amenorrhea or absence of periods due to some cause. Stress and anxiety is a major factor. Thyroid problems and abnormal levels of FSH, LH, prolactin, androgen hormones or male hormones and estrogen hormones too can be the cause. MRI of brain may be required to rule out pituitary tumors secreting prolactin. Another major contributor is polycystic ovarian syndrome (PCOS). This can be diagnosed by a CT scan or abdominal ultrasound and tests for insulin resistance. Smoking is also often associated with secondary amenorrhea and can be worse in presence of stress. Sometimes tumors of the ovaries and brain may also cause absence of menstruation. Severe anemia and malnutrition, excess weight gain or weight loss, hypothyroidism too can contribute. If you have been on pills or depot shots then this can be post pill amenorrhea. Hence please discuss this with your gynecologist and get yourself examined. Take care!