The answer is "it depends." Yes, selling your equities while the market is down locks in your losses.
Can you sleep at night with this riskier allocation? Can you wait it out until the market recovers? If so, then wait. Making the change gradually using additional funds is the better way to go. When the market recovers, then you can complete the rebalancing to the new allocation.
I'm assuming that you have other retirement savings as well, in your new job. If so, consider all your assets combined as a single portfolio, then add the bonds where you have more flexibility. Again, it's a bad idea to sell equities while the market is down, but your overall portfolio may already be in your desired allocation (or close to it.) If so, don't worry about it, and take care of it over time.