Feeling like I've let my deen slip...

Assalamu alaikum. Last year was tough for me, and while I didn't really leave Islam, I stopped following a lot of its practices. But alhamdulillah, I always kept my Ramadan fasts, no matter what. Recently, I pushed myself to reconnect with the Muslim community to strengthen my faith again, and it was a huge help-I started feeling much closer to Allah. Lately though, I've been struggling. A close friend has started turning away from Islam, and the way she talks about it is really affecting me. I've tried to distance myself, but it's been hard to do quickly. Her words got to me, and I've missed a few days of fasting. I don't blame her-I'm an adult and should think for myself. Honestly, I feel so guilty about it, and I'm planning to resume fasting tomorrow, insha'Allah. How do you all handle this kind of guilt? And can I make up for the fasts I missed? Also, how do I approach making up fasts that I skipped due to my monthly cycle?