My friend is torturing me

I had actually borrowed a loan of 40k from my friend and he said to give an interest of 10% which is 4k monthly. I had no option but for an emergency issue had to borrow. I had been paying him the interest on time but now I'm jobless and I have no money to pay... I requested him the same and I pleaded him but still he is harassing me asking for me to pay and abusing me aloot... There is no written document that j had taken a loan from him or agreement. He asked me to give a blank cheque with sign.. But that account is also closed it has been around 11 months since he lended me approximately I have paid him 44k only interest.. I also said him I will pay 20k in few days and remaining 20k in few more days.. But he is not accepted that and asking me to settle the whole amount. Is this valid.. I'm feeling alot of pressure from him I'm totally depressed.. I am regretting my life for this... Kindly help.. what is the step I can take to solve this issue... I am jobless since 2 month's searching for a job.. I am not able to manage it.. kindly advise. Please