I just lost my job - what do I do?
First of all, I'm really sorry - getting let go hurts and can be scary, but resist the temptation to wallow - jump straight into activity focused on landing your next gig.
Immediately, polish up your LinkedIn profile and your resume. It's fine to leave the "current" status on the job you just lost (until the month closes).
Call the most well-connected person(s) you know and put some feelers out there. You don't need to reveal that you lost your job, just that you're exploring options, getting a pulse check on potential opportunities.
Think about what you want to do next and create a job search feed on LinkedIn, Indeed, etc.
Evaluate your finances to see what auto subscriptions and other expenses you can cut out immediately. Based on savings and monthly expenses, determine your deadline for securing a new position. And while you're at it, figure out your minimum salary. Often times losing a job can lead to a really inspiring career change (which may also mean a cut in pay). Figure out in advance the minimum amount you can make so it's nailed BEFORE you start interviewing.
Once you've got all that done, network like a mother fucker. 85% of jobs get filled via networking. Join groups on LinkedIn; see if there are social meet ups tied to your industry in your town; reach out to every relevant contact you know.
And lastly, re: the job loss discussion, from a networking standpoint you can simply say you're looking for a new job. But when it comes time to interview for your next job, you'll need to be a little more forthcoming, as they will likely contact your former employer before offering you a position. Although legally your former employer is only allowed to state your start and end dates, I suggest you do some soul searching on what went wrong, and then think of ways to describe that (as truthfully as possible) to a future employer that doesn't sound concerning. Example - you were let go because your boss didn't like you, in an interview that's "different opinions on how to best move the business forward."
You get the idea. Good luck to you.