Is it OK to cry in front of your sister ?

Me and my sister are both pregnant at the same time only mine is two months after hers she's due in August I'm due in October. I've been really worried for my son lately since I'm diabetic I'm worried he might be to or worse I could loose him my doctor said he's healthy but stuff can happen. My sister doesn't have any health problems she's perfect so she doesn't have to worry about her daughter. I take my medicine every morning I only take it at night if I have to if my sugar gets high but it hardly ever does. I can drink Mountain Dew it doesn't bother me that's the only thing with sugar I can have it don't bother me. I drink it all the time but since I got pregnant I stopped drinking it. I've been diabetic since I was 10 I'm 21 I still have it. I'm so scared my son will get it or even worse. I'm not one of those girly girls who cry at every little thing I'm more of a tomboy I don't hardly ever cry especially not in front of others very rarely but me and her are really close. Is it ok to cry in front of her ?