I took university Japanese. Don't try to bite off too much at once. You should systematically learn hiragana first. Go down the chart learning one row at a time. Don't move on until you've mastered that row. As others have suggested, you should buy a workbook on Amazon. And there are lots of YouTubes on learning hiragana. I used Japanesepod101.com.
How are you using the flash cards? To begin, I would take only the cards of the first row, ka, ki etc. Practice writing them and say the sound out loud at the same time. Once you feel comfortable, test yourself. Mix the cards around, have only one side up and see if you can answer the other side. Then flip them around. Don't move onto the next row, until your test is 100%. But you must also review. As you proceed, include the flash cards of the previous rows in your self-assessment test.
Do not move onto katakana until you have learned hiragana. As you are a beginner, don't even try kanji. Kanji was not introduced in my course until the second year. You will be able to get by in Japan with hiragana and katakana.
Japanese is not an easy language for English speakers to learn. You need to put in the work and be very patient. It took one semester to learn hiragana and katakana.
It is very admirable of you to learn Japanese. You will have a richer experience. But equally important it to also learn the etiquette. I hope your PBS course includes that. If not, you can find information on YouTube or on Japanesepod101. Have fun studying.