istighfaar

Q: I drink alcohol but now I want to pray and I'm very nervous about it. What can I do?

Q: If a person says in a conversation about someone else that "was he the relative of Allah" or "Allah was not sleeping" but he did not mean to say it but by mistake he uttered these words without believing it by heart. Will his nikah and Iman distroyed? Means whether she has to do tajdeed e iman or tajdeed e nikah or only tobah is enough?

Q: Does thinking sexually in Salaah break Salaah or should I just say astagfirullah afterwards?

Q: Can we recite only istighfaar during periods or tell me any recitation which is allowed during period days?