I’m feeling really canonsick for my bf, but I’m a minor and can’t reach out. I’ve been looking at fanart of him and it just makes me sadder. Please help!
Frankly, in my opinion, a person shouldn't be reaching out to establish a romantic relationship with someone on the basis of their kintype no matter whether the person is a minor or an adult.
Kintype is a terrible premise to start a relationship on because it comes with all kinds of assumptions that might not be true. Each person will have assumptions and ideas about the person they're getting to know based on their kintype, and it can be very easy to do things that make the other person feel inferior or rejected when they don't 'measure up' to their partner's own personal ideal for their kintype. It can be very objectifying.
Its always wonderful to meet someone with whom you've had a relationship in another life, or as another person, but its important to establish a relationship based on who someone is now, not based on your own ideals and memories of someone who might not even be the person you knew. Just because someone shares a kintype with your boyfriend, doesn't make them the person you remember, and doesn't necessarily mean that they'll be anything like that person.
There's no guarantee that someone is from your canon, and even if they are, its entirely possible you've both changed in the meantime, and will be incompatible.
That isn't to say you should never get into a relationship with someone who you've been in one through mutual kintypes, but that it shouldn't form the basis of the relationship, or be something that you're actively looking for; as I've said because of the expectations involved.
It can be massively gratifying and wonderful when you do meet someone who you've been entangled with before-- my partner and I have been together through several lifetimes, which we didn't know when we met one another-- but going into a relationship on that basis can also be damaging and give people room to manipulate and hurt one another.
The best way to deal with feelings of nostalgia and canonsickness for someone from another lifetime is to celebrate their memory. Write down how you feel about them, or memories you have of spending time together. Make a moodboard, or some drawings. Do an activity that you used to do together and remember them.
Nostalgia for someone who was close to you as your kintype is like any other type of grief, the best medicine is to celebrate their memory and recall how and why they were dear to you.