If she truly has a history of suicide attempts, then she has had therapy, or even currently is in therapy. This is moving too fast even for a friendship. I usually take 3 months to know if I'm even going to be friends with someone IRL; sharing my birthday is a whole nuther level. But if she was open with you about her feelings, I would say to be open with her - that your feelings haven't gone where hers have gone, and that you are too preoccupied with other things (your health) right now to get involved. This is true; these are your boundaries. Tell her you didn't expect such an extravagant gift, and aren't in a position to be able to reciprocate, so you feel you should give it back to her, even tho you really liked it. You choose your boundaries and stick to them; that's all this is about. I totally understand your panic, but it's just this invasion.