Hey there, I'm also in a very long LDR due to the pandemic... I miss my boyfriend very dearly too.
I'm no one to judge your relationship, just want to share some light and advice from my experience...
It's been almost 2 years since I saw my boyfriend and we're 5 years apart in age, so naturally I'm more irrational and act out emotionally, sometimes have the weridest doubts. However, everytime these issues occurs I tend to always turn away from them and become passive aggressive, rather than talking it out.
Questioning, fear and doubts are normal. You said you're very young, I'm not sure exactly how young. But it's all normal. LDR is not meant to be easy. Growing is not meant to be forgiving. I've slowly learnt to see this over the course of my very first serious relationship.
I'm also struggling mentally on top of the pandemic fatigue, work, university and family issues, so I understand how difficult everyday for you may be. I don't know how much time it takes to determine whether she's or he's the one, but I believe in trusting each other, growing together and talking it out.
I can't emphasis how important it is to talk it out. It's super hard, not gonna denie that, it took me a while to get used to it. But things only get worse if there's no communication between you and her.
I'm assuming this LDR is making you feel insecure and maybe that's why you're feeling the way you are. I'm not saying facetiming is wrong, but find a right time for BOTH of you. My boyfriend is busy with his fulltime work, yet we would google hangout each night and leave it on, because we're both okay with it. Also we video chat every day too, nothing wrong with that if it works.
That being said, someone in this relationship needs to be the bigger man (or woman). This means being understanding, patient and forgiving, but also rational. In my case, my boyfriend was that bigger man.
Finally, I just want to reiterate the importance of communication in a LDR relationship. Believe me there will be times you want to give up, but take a breath and think logically. Don't let emotions take over you. Also try playing some online/PC games with your girlfriend, or watch some shows together with her! Find a time that suits both of you.
If this is the relationship you and her want to continue in, both of you will have to put some effort into it :)
Have 'the conversation' with her, exchange your thoughts and see how it goes.
Hang in there.