I would suggest going for clinical pilates for pregnant ladies. They can help diagnose the issue (could be the habitual posture or muscle related) and suggest work out. I started going when I was at my 19th week! Wished I went earlier. My initial sessions were upper and lower body review (check on flexibility, stiffness, some targetted muscle pressing to reset- not manipulation like chiro), followed by light exercises and stretch in each session. As I progressed along, the sessions will be more focused on strengthening your pelvic muscle, hip exercises. I tried prenatal pilates (one trial lesson) before but I find clinical pilates a lot more comprehensive in your well being. The one I go to cost around $250sgd/ session but so so worth it.
continue sleeping on ur side preferable left for better circulation and enhance support by placing 1 or 2 pillows between ur knees extending down to ankles to keep ur hips aligned