If it was a killstreak nuke, no big deal. Just keep working at it. I struggled for months trying to get a killstreak nuke, then finally I got one.
After you get the first, every other one is a piece of cake. In the past 4 months, I've gotten ~20 nukes including 8 killstreakless.
I'd suggest not going for nukes, however, and have your KS set to 7-9-11.