Two main tips (note that I used to run in Wellington, NZ which is famed for both its hills and its wind).
Firstly, a headwind is basically a hill you can't see - treat it that way. Techniques like small, quick steps to preserve momentum are most useful.
Secondly, for a sufficiently strong wind you can draft off people. Tuck in behind someone in front and let them tack the brunt of it.
No, I don't think a pack would have helped. Packs are about water.
Aside, I once did the headwind trick in a race. It was the 10km of a tri and I'm very much a back-of-the-packer. I was tussling with one guy with the lead changing a lot. This was in Wellington and very windy that day so I gave up and just huddled behind him until we rounded the last headland. Then I just pulled past him and cross the line in front.