A unit of 5 Necron Lords is ~bad~. Like horrifically bad. It has one potential use, which is countering small, elite units, such as Thunderwolves, which is compounded by poor Ld.
So it curbstomped you, big deal. Stuff happens. Doesn't mean that you're a bad player because you don't see the danger in a new tactic the first game you see it.
What's annoying is that you ask a vague question, giving no specifics, such as your army, then come back screaming that people aren't factoring the specifics into their equations.
For instance, you've given no indication as to their armament. Were they armed with Staffs of light or warscythes? If the latter, the unit costs at least 315pts with 5 scythes and a res orb. Thats an horrendous points cost for a small, vulnerable, slow unit that is only good at killing specific units. How much did those Thunderwolves cost? Did the Lords kill more of your stuff or was that it? Did you even lose the game?
You mention that they had an Overlord and Cryptek with them, which made things tougher. Why? Thats now at least 450pts in one place! Even to agree that they're an unbeatable unit ignores that you can ignore them, and hammer the rest of their army! Feed them something cheap to occupy them if you have to. If you can identify their transport, then hammer it with all those nasty Long Fangs. A Ghost Ark is AV13, but open-topped and only a single Immobilized result is neccesary to cripple their movements. Not to mention that the first successful hits makes killing it so much easier.
In the end of the day, you have to kill 5 T5 1W models, 1 T5 3W model, and 1 T4 1W model. They probably have a res orb, so get back up on a 4+, so its pretty much like doubling the wounds. You can't use an elite close combat units to kill them, but anything else will, at least in a points efficient trade. It takes an average of 27 bolter rounds to put down a single lord so I wouldn't advise that either.
As a Space Wolf player, you'll have a harder time than a Guard or Nid player, for sure, as bolters and blades is so much of your army, but you still have a lot of powerful shooting (Vindicators, Long Fangs) and cheap chaff (Fenrisian Wolves), so whittling them down or bogging them is all possible. Once there is only one or two left, then you can consider breaking them in one go.
I hope that is helpful.