Her period stopped for six months then it came back and she has been bleeding for more than three weeks

I am suffering from irregular periods. Sometimes I have no period for
five or six months. The point here is that I got my period three weeks
ago, and uptill now it has not stopped. Please note that the colour
and smellof the blood is that of menstrual blood. What should I do?
Should I pray or not? If I have to pray, should I make up any of the
prayers I missed?.
Praise be to Allaah.
The basic principle is that the blood that comes from the woman is
menstrual blood, so long as it does not last the entire month or
onlystops for one or two days (in the month), in which case it is
istihaadah (irregular, non-menstrual bleeding). This is the correct
scholarly view, sothere is no maximum limit for the menses.
The menses may increase or decrease, and it may come earlier or later,
or it may stop for several months.
Shaykh Ibn 'Uthaymeen (may Allah have mercy on him) said: Some women
may remain without menses for four months, then get the menses for an
entire month, as if – and Allah knows best – it is withheld and then
all comes at once. And somewomen may menstruate for three or four or
five or ten days every month.
End quote from ash-Sharh al-Mumti', 1/402
For more information please see question no. 131541
It is well known that the woman who is menstruating should notpray or
fast. As for the woman who is suffering istihaadah, she should pray
and fast, and her husband may have intercourse with her.
Based on that:
What is happening to you now is menses, so long as it does not last a
complete month or one or two days less than that, in which case it is
istihaadah; and take thisinto account for the following month.
See also question no. 68818 on what to do in the case of istihaadah.
And Allah knows best.