Sorry you're suffering OP, pregnancy is hard enough without added aches and pains. PP is right, look into a chiropractor, also speak to your midwife about the NHS course for SPD (although you can find out everything on the internet that they will tell you).
A few tips:
--Talk to your boss/line manager/HR/whoever about being a bit more accommodating with regards to being on your feet all day, maybe see if they can change your job around a bit to allow more sitting/less moving around.
--Read up on correct posture during pregnancy, as that one is so easy to do wrong without realising it and can make such a difference. Ie: keep legs together as much as possible, including on stairs, sitting and when getting in and out of cars.
--Look into some decent shoes for pregnancy, as well as a support pillow and support belt. All very much worth the money if you have pains. Just assume you have SPD at this point (although do still get it diagnosed by your midwife/GP) and treat yourself as such.
--Get an exercise ball and do gentle hip rotations/pelvis rolls on it, as this can really help with posture and relieving pain.
--Paracetamol as much as you can. I know it barely takes the edge off and wears off after like an hour, but it's better than nothing.
--REST as much as you possibly can. It's horrible to feel like such an invalid (especially if it's only early in your pregnancy) but you can make this pain worse by not resting.
--Talk to your midwife about this; they can be so helpful!