Need To Lose 20 Pounds By The End of September, Suggestions?

So, my sister is getting married in September and I got my bridesmaids dress a couple days ago. I'm a size 14. I'm horrified, never been this big in my life. I'm 5'3 and currently 175. I was 178 when I went and got the dress. My goal is to make sure that dress doesn't fit on her wedding day. I know, that sounds horrible because it will ruin her wedding, but I don't care, I want to be happy. What can I do to shed the pounds?

Currently, I cut out the entire bread group and rice. I'm only eating red meat maybe once or twice a week on days I do cardio. I'm doing cardio twice a week for 30-45 minutes after 45 minutes of weight lifting.
Need To Lose 20 Pounds By The End of September, Suggestions?
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