I think my sister got her period while staying with me. What to do?

My parents are out of the country and my sister is on spring break, so she is staying in a different state with me. We are usually close but all day she has been avoiding me. I couldn't figure out why and then I saw blood on her pants. She has been in bed all day. Do I go buy her something? Wait for her to talk to me? My girlfriend and me just broke up so there isn't a girl she can talk to. My college is on spring break too so all my friends are out of town. She's 14 and I don't want to make her feel uncomfortable. She is staying with me a couple more days. If this is the case she will need something.
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Update: By the end of the day I just got bored and sick of wasting time together so I went into her room and sat on her bed. I put my arm around her and asked if something was wrong. Tears started forming in her eyes so I just asked her if she got her period and she said yes. I told her she had nothing to be embarrassed about. I took her to the store and we bought some pads, food, rented a movie and then went back home and chilled. Went alright I guess. Thanks everyone.
I think my sister got her period while staying with me. What to do?
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