You have lost 3,00,000 USD in gambling 
You should have known the risk in gambling. This is a big amount and you could have invested this amount in some better business or property and could have gained good money but unfortunately you have lost it all.
I believe you should now have to forget about the past and look for online work through freelancing.
Exactly, that amount of money in my country is enough to build a business and buy a house and two cars, imagine if OP had saved or invested that money, not to mention that those money that he used from gambling came from OP's family based on what I can understand in OP's post. I don't think forgetting about the past is going to be good because that is a way for OP to learn from the mistakes that s/he did so as to not make the same mistake. I think OP is already looking for that online work but I think the sob story isn't going to be helpful in that avenue. You should have known the risk in gambling. This is a big amount and you could have invested this amount in some better business or property and could have gained good money but unfortunately you have lost it all.I believe you should now have to forget about the past and look for online work through freelancing.