I’m in need of some advice!

This is will properly turn out a little long, but I'll try and convey my situation in as few words as possible. I would also like to quickly state, that English isn't my native language, and therefore sharing chat screenshots would be pretty pointless.

3 to 2 years ago I[19m] went to a boarding school in my gap year. It was a great experience, and I ended up with a bunch of wonderful friends. Shortly after the school was over, me and this girl[19], who had also attended the same boarding school, let's call her Miss Piggy, kissed at a party. We had had some kind of chemistry before, but nothing especially noteworthy.
Soon I and one of miss Piggys mutual friends got into a relationship tho(They weren't really that close or anything like that.). We dated for over a year, but broke up like 5 months ago.
During the first couple of months of this relationship, I saw Miss Piggy almost every day, since we attended the same college. She was a kinda flirty all the time, and it was clear that her intentions weren't all platonic. I always thought she was sweet and funny, but back then I was in a happy relationship, so didn't give it much thought, and ignored her subtle approaches.

Miss Piggy ended up dropping out of college, due to reasons that were out of her control. She moved back to her home town, not that far away, but still, I almost didn't see her anymore. The months passed and she got into a relationship, with some guy I don't know.

Yesterday I saw her on Tinder, swiped right, and a couple of hours later she super liked me. We chatted quite a bit yesterday, and it was clear that we were still able to speak about deep shit, even though it had been over a year since we talked for real.
Turns out that she has gotten a serious depression and that everything kinda sucks for her. She broke up with her boyfriend recently and it just seems like a mess to be honest.
Even though some of the topics of conversation was very serious, she kept being positive and just writing with her made me feel a little fuzzy due to all the nostalgia.

Now comes the question, how should I approach this girl? She seems interested. Like she responds instantly, super liked me, and so on. I'm just scared of hurting her, and she seems very vulnerable at the moment. Depression, breakup and so on. I don't mind that people have issues, that's completely okay, and not really a huge red flag to me.

She might just be looking for a quick rebound, and that would be perfect since I don't want a committed relationship, I at least don't think so. What I'm scared of is accidentally "just using her", when she is in such a vulnerable state. If you guys know what I mean…