The only way people will be losing money in the long term with investments in a bourse is if the company they have bought shares in goes bankrupt, or if they panic sell when share prices start to fall (as is the case with most people).
So if you have made a sound investment by buying shares in a company such as an oil, pharmaceutical, processing, etc company and do not require liquid money within the next 3-6 months, then just hang in there. Global Bourses will recover, Inshallah :P