It’s way more important to be able to play it cleanly without the tab than to play it fast with the tab. The tab is a great learning tool, but it’s a lousy crutch. If you go to a jam, there’s a good chance you won’t be able to keep up if you rely on the tab.
Break the song up in to as many pieces as you need to in order to memorize it. I’ll start with as little as 2 measures and just play it on repeat until my fingers play the notes automatically. Then go on to the next 2 measures, learn, then combine what you know. Keep on until the whole song in locked in.