Learning multiple languages simultaneously can seem daunting, but it is actually a lot more simple than people think. In order to learn a language, we must dedicate time and effort in order to gain fluency. The thing is, it is possible to study both of your target languages at the same time.
When I went to university in Venice, Italy, I majored in Mandarin Chinese. All of my classes were in Italian, (my 3rd language), and I wasn't sure how my brain was going to be able to manage the intricacies and nuances of the Chinese language through Italian. The thing is, I was able to pick up Mandarin faster because I was forced to really understand the grammar and vocabulary because I was learning the translations in different languages. I would read the summary in Italian, and then create flashcards in order to learn the Italian translation in Chinese. This helped me spend my time learning and expanding my Italian and knowledge of grammar through a new language. I would write notes in English summarizing the grammar connections between all three languages. It took some getting used to, but at the end of the day it helped me solidify my two non native languages even more.
I enjoyed it so much that I began studying each new language I learned through a previous acquired one. I learned my Japanese grammar and vocabulary through the Mandarin I had studied, and then learned French through Italian! It was amazing how my brain seemed to click when I used a plethora of different languages in order to learn a new one. So, if you are nervous about studying multiple languages at once, have no fear! It is easier than you think and actually fun!