Hi,
Thanks for the query.
As your urine
pregnancy test was negative after one week of missed period, the possibility of pregnancy is less.
If you want to be sure about the result better to go for
blood test for pregnancy.
If the test comes negative, the possibility of pregnancy is very less.
The intermenstrual spotting and
irregular periods you are having could be due to
hormonal imbalance.
This can occur due to stress and strain, weight changes etc.
The symptoms can change from cycle to cycle depending on the severity of hormonal imbalance.
So you once consult gynecologist, get examined.
And go for
ultrasound if she suggests.
Then you can take tablets to induce withdrawal bleeding with your doctor's advice.
If the irregularity repeats, you can use hormonal pills for few months.
This will help in regularization of the cycles.
Take care.