If it is reasonable for you to continue with postgraduate studies, I would recommend that you do that. The more math you can do or know the better. And it is going to be harder to gain those skills once you leave university.

You haven't mentioned any software skills. I would recommend develop whatever skills you have in that area. The ability to program is becoming as important as literacy and numeracy. Even more so for a mathematician.

My bias is that I have a PhD in math and have been a software engineer for the last 10+ years. I have worked in a lot of different areas and that has largely been because of the combination of math and software (and luck).