I know how frustrated and devastated you feel! I also have been dealing with acne off and on my whole life and often get the deep cystic pimples on my cheeks and jawline. I'm not a doctor, so I can't give that type of advice, but it's my understanding that it takes probably 2-3 months to see a positive change in your skin. The combination of antibiotics and birth control sounds like an effective combination. I would give it at least another month before you re-evaluate things. The antibiotics might start kicking in soon and you'll be feeling much better.
You might also consider seeing an aesthetician. I found that when I did that in the past they had some good recommendations for me.
Also, I've been noticing on the internet that there is a connection between dairy and acne. Do you drink dairy? Also, watch any refined carbs, like white flour and white sugar and drink plenty of water.
Hope that helps!