The brake system is not building pressure for some reason, and you'll need to look everything over to determine why. I would check all the brake lines and connections again, and also make sure the brake fluid is full, and didn't empty filling the calipers.
You may wish to try bleeding again if nothing is obvious, being sure to keep tabs on fluid level. Bleeding should hopefully give you an idea what'* going on. Unless your brake booster magically decided it wasn't doing enough to help you with the brakes, and cranked the assist up to 11, but that would be apparent when you try and bleed the brakes, because it will be making ALL the pressure.