Cats do this. The smaller the cat the quicker the problem happens. On bigger cats stuffing the bow past the front crossbeam usually happens just before you break something really expensive. On very small cats it's part of the fun. You are not going fast enough to hurt yourself and the boat is easy to right.
From what you said, the boat doesn't pitchpole easily. It just digs it's nose in and goes real slow.
First, try raking the mast back. Rake the mast back until it gets hard to steer or something else bad seems to happen, then rake it forward a little.
Second, Keep your weight to the rear of the boat and hang on. If you go sliding forward, the boat will probably flip over.
Third, Ease the sail. When the nose digs in, release the jib or ease the main. As you get better you will do this just before the nose digs in.
Fourth, If the boat is small enough and light enough use you weight (manhandle it). If you have hiking straps. Sit to the rear with your feet under the straps. When the nose STARTS submerge, lean out and back and pull up with your feet like you are trying to pull the nose up. Sometimes it works
Fifth, Have fun.