I need advice:

I have been having pregnancy symptoms for 2 almost 3 months now. Last month they did a urine and blood test and they both came back negative. Has anyone ever had a blood and urine test come back negative? Is it possible I could be pregnant? I had 1 period but it wasn’t as long or normal like they usually are. I also had an ultrasound done but they said they only seen cysts but at the time they did the urine,blood and ultrasound I would’ve only been maybe 3-4 weeks would it have been to early for anything to show up? I had my normal 7 day period in July then August it was 18 Days late and 4 Days Long... if I do start my period it’s supposed to start Friday. I’ve also gained 6 pounds from my appointment the first of this month until now. I’m bloated, constantly nauseous (mornings are the worst and after eating) and I seriously am miserable I could sleep all day if someone let me.