Can you go from 130-110 LBS? 3 people say pregnancy ill get whatever?

About once or twice a week i'll weigh myself to just so i can know how much i weigh so i cant tell my doctor or something like that. Anyways I wasn't really trying to lose weight i know my weight was 130 on the 24th and on the 27th it was 110. Is it possible to lose that much weight in that short of amount period during the 3 days i didn't eat well i couldn't really because I was vomiting so much and nothing would stay down except crackers but i didn't wanna live off crackers. ginger ale didn't help neither sierra mist they made me things worse with the vomiting. I was on the phone with my cousin and she said that it did happen to her before she found out she was pregnant she lost 20 lbs and that day took a test she got a positive. I thought it was weird how one day my weight was and has been 130 for a while and then 3 days later its 110 im pretty s