Physio is great IME but it does require lots of repeating the exercises, so can take a couple of weeks to feel any difference. I find a ball very helpful to do the exercises on.
I'm also finding specialist massage (Myofascial release) very helpful.
I've been doing gentle exercise (walking, pilates squats and swimming but no breaststroke) in the pool - I find that as the water supports my weight I can do a lot more in there and it gives my pelvis a rest just to be in the water.
Learn how to engage your pelvic floor and lower ab muscles and try to do this before doing anything, e.g. getting in/out of bed/car, getting up from a chair, using the accelerator in the car.
Painkillers work best if you take them before the pain gets bad and if you take them regularly, so take the paracetamol if it's okayed by the midwife/GP. And you can have codeine too if needed (but def check with the GP first).
Avoid slouchy chairs or any chair where your knees are higher than your hips, or where the rim of the chair is higher than the seat part (like some cafe chairs) - take a cushion with you when out if this is an issue.
Rest with your legs up whenever you can. Sitting in a chair doesn't relieve much pressure from your pelvis - you need to get your feet up.
Be careful with your alignment in bed and always use a side sleeper pillow.
I didn't find stretchy support pants/bands helpful but that's because I have hypermobile hips and they put pressure on my hip joints, causing them to partially dislocate. I haven't yet tried a physio belt.
Good luck!