HELP, CHANGE MY DIET!!!!!

A💓C • Married, 33 yrs old pregnant with our 3rd. I haves 2 boys ages (14/8) and praying for my little girl.
I need to change my diet, I will be 6 months on Tuesday and I have gained about 20-25 lbs which i am NOT proud of. I know with the holidays it was extremely hard especially having host our family gatherings for Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a>, Christmas Day and New Years <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> at my house. I'm done with food. I need help changing my diet to better foods so that i do not gain but AT THE MOST 10-15 lbs.  What is in your diet??? What are best snacks, breakfasts, lunch and/or dinner. How are you keeping the lbs down? I know I should exercise too but with the pelvic girdle pain and sciatica nerve since early on in my pregnancy i was in to much pain to work out.