Stock options from private company

[sagdd]

I had purchased/exercised stock options for a startup(which was private) i worked at 5 years back. Last year the company got acquired but my stock options became worthless since the company was sold for a loss.

How do I claim the loss on my tax form? I had also paid some tax on unrealized profit the year i had purchased the options, can i claim that as my loss and how do I do it?

I haven't received any documents from the company.