I had all those pains with both my pregnancies. And horrible painful gas with my first. There is nothing much they can do before 12 weeks. But you should Remind them how far along you are and push for an appointment with someone. An ultrasound will put your mind at ease :)
Gas is normal, and everything you are describing is what i had after my miscarriage in april, i am now 19 weeks with my rainbow baby, he is very healthy. And if this is your first baby, you will barely show within the first 20 weeks... my son whos 7 now, i started showing with him at 6 and a half months... my daughter whos 14 months around 4.5 months i was showing with her... with baby number 3 im barely showing. And i am having the same problems u are.
Mine are a mixture of my previous misscarriage and my previous c sections.
With my son i didnt have an ob until i was maybe 15 weeks along.. my daughter 20 weeks and this one i got right away. It all depends on how booked they are. And if you are really worried, ask your GP to have an ultrasound booked for you. They cannot deny you that in pregnancy especially after a misscarriage.