Instead of 1/ 1/2 hours twice a week, exhausting yourself, I'd try 3 days a week, an hour (or less) each. Sometimes more isn't better. And hitting the weights more frequently, rather than longer, may give you the boost you need.
No, I'm not a personal trainer, but I read A LOT, and I've been working out, and studying about fitness on my own, since around 1980 (with some major gaps here and there). (I'd like to think that my PhD in French makes me able to do research and be an autodidact in other fields as well!).