Could I be pregnancy after a negative test?

so I’m very impatient and took 2 First Response 6 days sooner tests today, a week before my expected period. They are both negative. But I’ve had a lot of mild cramping in my lower back the past 2 days. I’ve felt nauseous whenever I eat dinner the past few days. I’ve been sooo dizzy/lightheaded and have had some headaches the past week but it can’t be because I’m dehydrated because I can’t seem to drink enough water because I’m constantly thirsty, which is not normal for me. Could I be pregnant and it’s just too early to tell?