What you mean by "lunge" is probably, your horse going around you in a circle, right, say 10-12 feet away? You can get away WITHOUT doing that, in my opinion. But the kind of lunging I think tinyliny means is to have your horse MOVE, not necessarily trot or anything, about 4-8 feet away. This is more often called ground work, but it's a slower, step-by-step lunging, and you should do a lot of it at this stage.
I would go ahead and saddle but leave a halter under the bridle. Then, whatever I do on the ground, like yield her head to the rein, I'd then get on, and do it from the saddle. Then get off again.
Keep the lessons short, specific, and afterwards, see if you can't go for a leisurely, no-stress ride. (It's so disappointing if you can't ride at all! But I found with my horse, when I re-started her, the slow, step-by-step minutes were well worth it in relaxing her.)