Question about morning sickness

For over a week I’ve been throwing up. Then on Monday and Tuesday I did have some mild nausea but I didn’t throw up. Is that normal? I’m concerned because when I tested it was negative but I have symptoms that suggest that I could be pregnant. Such as sore breast, a lot of gas, back pain, cramps that feel like my uterus is stretching and of course a very late period. I do plan on testing again, I just want to wait another week or so. I’m just worried that this may all be in my head and that I may not be pregnant. But I’m not the type of person to want to throw up every day without some reason. Maybe I’m overthinking it or I’m just scared of getting another negative. Has anyone ever have morning sickness just stop or ease up as quick as it started?