LATE PERIOD OF 22 DAYS. Is back again?

I HAVE ONCE VISITED TO THE DOCTOR LAST YEAR DOCTOR ASKED FOR HORMONES TEST BY CHECKING THE REPORTS SHE SAID THAT IAM GOING THROUGH VERY SLIGHT HORMONAL IMBALANCE AND PRESCRIBED ME TO TAKE DRONIS 20 ,CALCIUM & VITAMIN D TABLETS FOR 3-6 MONTHS SO THAT I WILL BE OK .I HAVE USED IT FOR 6 MONTHS STOPPED IN JANUARY .AFTER STOPPING I AM REGULAR TO MY PERIODS FOR NEXT TWO MONTHS I.e., 28 day cycle (FEBRUARY,MARCH) .I HAD MY LAST PERIOD ON 11TH MARCH . AS PER THE FLO APP I AM SEXUALLY ACTIVE AT THE TIME OF OVULATION.I MISSED MY PERIOD TAKEN URINE PREGNANCY TEST AT HOME ON 13th APRIL ,17th APRIL,21st APRIL,1st MAY .ALL ARE NEGATIVE .I AM FEELING BURPING,SOMETIMES VERY MILD LOWER ABDOMEN PAIN ON BOTH SIDES ,GASSY STOMACH FROM THE DAY OF MY MISSED PERIOD,FEELING THIRSTY ,MILD LOWER BACK ACHE .I AM EXPERIENCING THESE SYMPTOMS FROM LAST 20 DAYS.CAN I BE PREGNANT OR MY HARMONAL IMBALANCE IS BACK AGAIN ?PLEASE SUGGEST ME