Yes, their huge and sudden growth has completely changed the old 2-block system. The old political parties were very worried that they may lose power, so they struck a deal that none of the old established parties would cooperate with SD in an attempt to reduce their influence. Polls now show they have approval ratings as high as 15-20 percent. Yet no party will cooperate with them, this is largely due to the fact that the (overwhelmingly left-wing) media has demonized them to an absurd degree with the enthusiastic aid of politicians from all other parties hoping to stop SD growth. Now even if some party wanted to cooperate with SD they would be unable to do so because they'd be working with the very people they publicly called literal nazis just a few years ago.
This has lead to there being 3 political blocks. The left, the right, and the Sweden Democrats as the lone party in their own unofficial block. The right lost a large number of voters to SD leading to the loss of the right wing in the recent election. This lead to the left wing block winning despite the fact that the majority of the population voted for either the right wing block or SD.
The left wing had not ruled in almost a decade and they were ill-prepared for this victory. They made questionable decisions when assigning ministerial posts, and could not come up with a budget. This general chaos and the lack of a budget would have led to a re-election were it not that the main left wing party decided to abandon many of their promises and struck a deal with the right-wing block to remain in rule, but to do so using the right wing block's budget.
This chaos and the backroom deals to cooperate with their direct opponents lead to distrust from all the voters and further increased SD's popularity. The sudden upswing in SD popularity also lead to the traditionally very left leaning news media to start acknowledge that up to a fifth of the country would stop buying their papers if they contained as many anti-SD articles as they used to.
But this is not saying that everything is going great for SD. Their main man is burned out taking a long vacation, his replacement has a bad case of foot-in-mouth syndrome leading to many-a quotes on news paper covers. The party is also growing too fast for their own good. They're having trouble finding enough competent people with the squeaky clean backgrounds needed in this day and age when the journalists are openly working with criminal hackers that dig up any dirt they can find.