@nishchitha: are you able to see the previous workspace listed — or is it gone from your list of workspaces entirely?
If you can see it listed but it won't load, there may be an Analytics outage. Sometimes clearing your browser cache or using an incognito window can fix this issue.
If you can't see it at all, is there a chance that you "saved" over the previous workspace?
If you built the test workspace off of the previous workspace, saving it would override the previous work.
To create a copy without overriding, you need to 'Save As.'
Deleted workspaces cannot be recovered.
However, if you shared the workspace with others or set up the workspace for scheduled delivery, you may be able to retrieve it. For example, if you set up a scheduled report, it may still like in the 'Scheduled Reports' section.
To check, navigate from Analytics to: Components > Scheduled Reports.
Hope this helps.