PREGNANCY SCARE HELP!!!

For the past few weeks I have been waking up at the same time around 3-4am and vomiting and I've been every fatigued and sometimes even dizzy. I told my mom and she thought I was pregnant but when I took 2 tests they were both negative. However my mom knows someone who was pregnant and produced negative urine result because there wasn't enough HGC in her body and the blood tests came back positive. My mom made an appointment for me to have my blood drawn tomorrow and I'm really scared they might come back positive. I'm only 17 almost 18. Help!!