I have committed many sins which no one knows of except Allaah. What do I have to do so that Allaah will accept my repentance?

I am one of those who send blessings upon the Prophet between 50 and 100 times a day, according to circumstances. I say: “Allahumma salli ‘ala Muhammadin wa aali Muhammad (O Allah, send blessings upon Muhammad and the family of Muhammad).” There are some people who tell me that my sending blessings upon the Messenger of Allah is lacking. Can you tell us – may Allah reward you with good – what is the ideal way to send blessings upon the master of mankind, and is the way I am doing it really lacking?

What is the rulling on, when a Muslim say "We believe we are all children of Allah" Basing it on the weak Hadeeth (All creations are sustained by Allah). Please provide details of the ruling.

I used to be very sinful, my most beloved hobby was to sin. I used to take drugs (hashish, pills, and wine) and I used also to commit adultry.
By Allah’s grace, I repented from the sin of adultry before marriage but the sin of taking drugs remained. It was because of the bad companions I had. Then one of my cousins died, he was of similar age to me. But he was not married, I thought about my situationand that someone who is younger than me has passed away, and we were comitting the same sin togeather, taking drugs.  
Allah has guided me by His grace, so I gave up all sins, I even broke the satellite dish. My life has changed 180 degrees. I became charitable, pray, call people for good and denounce evil, distribute tapes and booklets and attend lectures.
The problem:

I face criticism, starting from family, mother and sisters, that I am strict. They want to listen to songs and watch series on television. If I advise them and say that what they are doing is haram they say: “why is istighfaar (seeking Allah’s forgiveness) prescribed?, If you do not want to listen to songs and watch television then leave, we want to watch and listen” the same problem happens at work as well, I have left home more than one time, my wife stays with them, I take her with me when I leave, but they ask me to let her stay with them. I refuse and my wife feels embarrassed and fears her situation causes any problems. But when I leave her with them, she sits far from TV and from where they sit.  Sometimes I hear my mother making du’aa against me saying: “I wish Allah did not guide you, you made us restless” I seek refuge with Allah from what she says.

My problem at work is, that I work in a military sector, all colleagues are bad, the religious ones are only three, there are six bearded brothers. They get over so many things, the rest of them take hashish and drugs, flirt women and majority are of course smokers.

They all agreed on insulting me, whenever I sit with them, they remind me of my past. They mock the bearded brothers, slander them and describe them as (liers and terrorists) and I feel jealous for them and say: “you are slandering your brothers, they are muslims, you should not mock the beard because it is sunnah to keep it”. Sheikh, they gave me bad reputaion, they always critisize the bearded brothers, they never mention anything good about them.

Is letting my beard grow, abiding by sharia, enjoining good and denouncing evil in this time a crime that I have to pay for, or become immoral like them?
Even my boss, he says: “you bearded men, I will put you under the misoscope, I will not forgive any mistake you do”

I have tried some solutions:
Firstly: I asked to move to another administration, but my request will take some time.
Secondly: I cut my relationship with everyone insulted me by a word or an action. This helped limit the problem. But I do not like this way, as people became careful when they deal with me and fear that anything they say may be disliked by me. So they dislike me and make others dislike me as well.
I wish you provide me with the suitable solution for my problem because I became really tired of it.