Pregnancy symptoms, but neg test

I am 24 years old, and I have very irregular cycles. Since March it's been 63 days, 45 days, and so far I am on 47 days and nothing. I am nauseated all day, I have had a constant dull headache for the past 4-5 days, I am moody, I have a loss of appetite, I have mild cramping, lower back pain, and constipated. I took a HPT and it came back negative, but with my cycles, I am not sure if I tested at the correct time. My last period was June 18. I have a dr appt tomorrow, but I was just curious if you could give me a heads up as to what is going on with me.

Thank you!