The best essays have a common feature: they are well-researched. Does that mean you don't need it? Now that you're calm and confident, you can proceed further.
The goal of your initial research session is to give you just enough material to start writing. Make the Introduction and Conclusion Solid You already have your thesis statement in the intro.
Once you're sure that the structure of the paper is fine, you can go with the final proofreading. If you find that you need more info after you start writing, you can always do more research.
It could be a chocolate bar, the promise of watching an episode of your favourite television show, or an evening out with friends — anything that will provide sufficient incentive to get your essay finished.
Afterwards, see that you have no errors or typos.