I had never even heard of SPD before I got pregnant with my first, I mentioned it to the MW at about 18 weeks and she said to me "some back pain is to be expected in pregnancy" I said it's not my back it's my tailbone and hips but she was next to useless
Next pregnancy at least I got some physio and a belt but TBH I don't think it helped much.
This pregnancy has definitely been the hardest with regards the SPD, I second whoever says night-time is the worst, luckily DP does most of the night wakenings but sadly he can't go to the toilet for me I find I spend all night in the one position and wake up really stiff, also I have to sleep propped up on my v-shaped pillow because of my sinuses and snoring so am not very comfy.
I know what you mean Minnie I have had enough of being pregnant too.
My SPD tips are do as little as possible, have rests when you can, I have to force myself to sit down every hour or so. A nice deep bath every night can help as well.
Luckily I don't get hayfever, feel so sorry for sufferers.