After putting Lysandus to rest by taking care of Lord Woodborne, you will hopefully have a little breathing space. If you tackled Lysandus's Tomb at 10th level, you should have a couple more levels before the next major quest kicks in (emphasis on "should" -- it's a little flakey in this regard).
Your next quest is going to be to retrieve the Totem of Tiber Septim. That's the Magical Dingus of Ultimate Power that everyone seems to be so hot to get their hands on.
Once you have the Totem, everyone who likes you will send you a letter offering rewards for giving them the Totem. On the other hand, everyone who dislikes you will just send thugs to take it off of your dead body, and the thugs show up just about every night (makes it difficult to get your beauty sleep).
So decide very quickly how many nightly hit squads (three thugs per group) you can handle and then spend your time building rep with as many people as possible to avoid getting thugs from them. The two major players that you cannot do quests for are the Underking and the Emperor, but they tend to be somewhat tolerant in the negative rep department. Everyone else (Gothryd, Gortwog, Eadwyre, Akorithi, and the King of Worms) can and does send thugs.
Use your breather wisely.