Feeling down about my future body...

I'm posting anonymously because i don't want people to hate me. I would actually like some reassurance or advice or anything helpful for the way i am feeling. So i am in the 2nd trimester now, so far this pregnancy i have lost over a stone due to morning sickness. The last couple of weeks i have not lost or gained anything. Anyway, i am about 56kilos now, but i am not toned at all really. I have a very loving and supportive fiance...but this week i have been feeling really emotional about what i am going to look like after pregnancy. I fear i will have a saggy belly and an ugly body, that i will struggle to lose weight, that i will be depressed and not want to have sex anymore 😢. I know it probably sounds shallow and awful but i am worrying about it. I have started to go to the gym and i am eating much better than i was pre pregnancy. Does anyone else feel this way? Will it be ok? what can i do make sure i don't end up depressed?