[ging]

Hello my last period last month ended in 13, and we have have sex with my husband. But after a few days I felt that I am pregnant I took a pregnancy test after 3 weeks during night its positve two lines came out. But I wondered if I this true because my period is irregular I mean sometimes it will come on the first week, or second week of the month or last week of that month.

[Curlyben]

Much too early to get any sort of meaningful result.
You must wait till your expected cycle is late, by about a week for a true result with FIRST morning urine.

[ScottGem]

If your Sept period ended on the 13th the, its too soon to take a test, especially if you don't follow instructions.

Wait until the end of Oct.

[Fr_Chuck]

Agreed, while a false period is seldom, the issue is you need to test in the morning, and need to be at least two week late to period.