HI, thanks for using healthcare magic
Pregnancy detects the HCG hormone, this is detectable by day 11 to 14 after conception.
If this time period passed when the tests were done, it means that you are not currently pregnant.
Persistent
nausea can be related to causes other than pregnancy such as : (a)infection
(b)side effect of medication
(c)liver or kidney disease
(d)reflux
(e)
gall bladder disease
(f)electrolyte disturbance such as abnormal calcium
(g)alcohol use
If it continues then your doctor can assess you by taking a history of your symptoms and examining you, to determine the cause.
Abnormal bleeding can occur due to any
hormonal changes which can be due to emotional stress, physical illness, infection, fibroids,
endometriosis.
In some cases the cause is not known
It is possible that this will not recur so you can monitor for now.
I hope this helps