Thanks for the query.
Not having cycles for 6 months, without symptoms of nausea, an increase in belly size and vomiting, tiredness, increased urination, is unlikely to be due to pregnancy.
Kindly consult a gynecologist for an examination and investigations like blood, urine,and an ultrasound test. It could be due to polycystic ovarian disease which causes irregular cycles, and can lead to weight gain. Thyroid disorders, anemia, stress, etc can also be other causes. The doctor will help int treating the condition accordingly.
Hope this helped.
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