Pregnancy weight gain

I've never had a problem with my weight or body image before getting pregnant. My BMI was always healthy. I'm 23 weeks and 2 days along. Every time I go to the OB/GYN I am amazed at how I'm gaining weight I never had before, but it's been in small increments. Recently I've looked at myself in the mirror and felt really ugly. In the last 4 weeks I've gained 10 pounds - which is a big spike for me - and the doctor says I need to be careful. (I have been eating a lot of carbs and had some stress this past month with finances.) At the next appointment I'm having my glucose test for gestational diabetes. I'm really nervous... I know I need to exercise and eat more fruits and veggies. Someone please just tell me it's going to be ok and that I can still make things better. I feel like a failure.