Thanks for the query.
Menstrual irregularities like inter menstrual spotting, change in the length of the cycle etc. can occur due to many causes.
Though some of your symptoms can be seen in pregnancy
just by that pregnancy cannot be confirmed.
So you once go for blood test
for pregnancy which will rule out the possibility.
If the test comes negative better to consult gynecologist and undergo physical examination and ultrasound
to find out the cause for your problem.