.After 3 days, i observed another bleeding, with the characteristics of menstruation.It is going on for 4 days now and I want to know if I should carry on the acts of worship or not.I have to mention I have some affections of the cervix and I am under hormonal treatment.I am afraid that is the cause of my bleeding.
A woman must refrain from fasting and praying if she gets her menstruation.
It is not necessary that a menstruation comes on time or for the same number of days, though this is the usual.
Therefore, if a woman sees her purity after her menses and then gets it back again, she should abstain from fasting a praying.
But if the bleeding exceeds being normal and it becomes continuous bleeding, in this case this is not considered to be menstruation. It becomes Istihadah.
In your case, it appears that your menses was over and you had 3 days of purity and then it came back again. Because you are saying the it has the same characteristics of your normal menses, this means that you have to stop until you see your purity.
This might go on for another week or so but if it accedes a week, then you should treat it as Istihada, and Allah knows best.