Help with TI breathing

Hi guys! I've been practicing TI for 4 months now, in fact I just started swimming 7 months ago. I've been doing the TI drills religiously but my biggest concern is breathing. I feel comfortable with the balance drills, and I've been doing drills like skate-breathe-skate, skate-stroke 3 times-skate-breathe. My problem is that when I incorporate full stroke swimming + breathing, I cannot get air, like literally my mouth is under water. I tried to follow the chin-follows-shoulder approach, but still I am not getting air like I'm supposed to. I don't know what I'm doing wrong. I am getting to the point of being frustrated but throwing the towel is not an option. Any advice please. Thanks.