15dpiui today result bfn

My cycle is 24 days and regular , my period lasts for 4to 5 days , its my 2nd iui ,taken letrozol 7.5 mg from my period of 4th day to 8 th day and my trigger shot is hcg10iu ,trigger on 6/02/2020 and iui on 8/02/2020, i have tested on 7dpiui the result is different with same urine ie 1st one negative and remaining two are faint lines ,after i tested at 10dpiui and the result is one negative and one is very faint line with same urine, i tested on 12dpiui one is positive line and 2nd is negative and 3rd is vvfaint line , on 14dpiui one is faint line and 2nd is vvfaint line these all tests are done with same urine but different result ,my due date ie 21/02/2020 my legs are full paining from yesterday night to now but some better and started at night pain from now better ,22/02/2020 15dpiui result bfnegative and iam using duphaston 10mg tablet from 15 days till now . Iam pregnant or false positives ? My period is due of using duphaston tablet ? Only one pill per day at night ,iam totally confused with the result its positive or negative ,please help me confirmation this positive or negative