Am I wrong for being jealous? What should I do?

I'm 20 years old and I started dating my girlfriend 2 months ago. Before I discuss the main problem let me tell everything, we are both in the same class so we meet everyday, but we both have a secret relationship (from our parents, for reasons, and they cant know of our relationship) that means we don't do many things after that. We've spent great time missing classes and have driven 400 km in this time to places. Another thing, I've been in depression for an year now, and it affected my sex life with her, but i've taken pills (she accepted happily), and we spent quality intimate time atleast once a week, and we both love it.

I care too much about her, I'm too patient with her. Whenever she's feeling low, even without reason, I make sure to get a smile of her, even if it takes hours. But whenever i feel low (more frecuently), she gets "mad" and an argument starts between us. I know she cares about me, but she doesn't show as much as I would like to, I mean, I don't feel I'm her first priority even when she has said that many times. But she does feel that she is the most important to me.

Now the problem, I feel like she's too close with her male friends. There are these 3 guys. First one "X", she talks to her everyday via text, this guy used to like my girlfriend and she told me this. The 2nd guy, he has told her countless time that he likes her and dedicates her flirting songs and stuff (even recently, she said no, again), and she goes exercising with him 3 times a week and tells me that they've been good friends for long time and that he "cares (haha)" about her (once she said that he cares even more than me, it hurt cause that wasn't true, and she knew it). The third guy (he has girlfriend), was her friend long time ago (had an arguemnt an stop talking) and texted her some days ago, and they have started meeting again like no problem. This guy also was bestfriend of her ex. After the first day they meet (she went reaaaally attractive to meet him), she changes her whatsapp status something about "memories", it ended up being something about her ex: she doesn't care about it but she did change the status. And now she is starting and meeting this guy with routine and I don't like this.

To end this, I don't like her spending this much time with these guys, especially last two. I get really sad when I know that she talks to them and I dont always tell her this is the reason but she knows, so she gets "mad" at me for being sad again, and this goes on.

I really want to know if I'm wrong, I asked her if she would feel jealous/bad in my place and she said yes... Any advice??