Accepting a gift of money from the contractor

Q: I am an Egyptian engineer working in Saudi Arabia, and before that I used to work in Iraq. During my work in Iraq, I oversaw the extension of a sewer system in a Shiite area. I prepared price lists and account statements. At that time, there was a contactor who carried out the operation from the beginning. The contractor was good, loved by the supervisory body in the municipality, and was the only nominee for the job. When the contractor knew that I was the engineer in charge implementing the operation, he met me and said that he would give me 10.000 dinar in return for helping him in the work, i.e. I would supervise the work.After the work had been entrusted to the contractor with the same prices that I prepared for the job, (it should be noted that prices were determined before the contractor met me), they were high because Iraq was in the state of war. I could have reduced the prices but I did not. I thought that the sum would go to the government to buy weapons and use them to fight and kill Muslims in Iran. Later on, I discovered that the contractor gave me the money in order not to change the prices because I could have done that.Dear scholars, this was the reason to take the money from the contractor and only for your information, I did not help the contractor (Part No. 23; Page No. 540) much and the quality of work was according to the specifications and technical requirements.Dear Scholars, I took this sum and spent it all except for a house which I built in my hometown with the money I received and I got married as well.I always think of this matter and can barely sleep at night because I feel terrible about taking this money and I was mistaken. What should I do?Dear scholars, what should I do if the money is ill-gotten and I cannot repay it or give it to the needy? I do not have anything except a house in my village where my wife lives, and my mother and my younger brothers will also live there.Dear Scholars, I have a mother and four young brothers, the eldest is 11 years old. My mother is old and my father passed away and did not leave us anything. Is it permissible to write the house in their names in order to feel relieved?Dear Scholars, could you issue me a Fatwa in order to be free of guilt? What should I do if the sum is ill-gotten? Taking into consideration that there is nothing left of this money except the house where I live.Dear Scholars, is my marriage with this money invalid because (Part No. 23; Page No. 541) I paid the Mahr (dowry to a bride from the groom) from it?