I am so glad you are reaching out!
What a good friend!

I do hope our responses will help your girlfriend and you.

The most responsible advice we can offer is to stress the importance of proper professional evaluations/interventions. As soon as possible.

Please encourage your girlfriend to seek professional help from her Primary Care and others. I am hoping her PCP will set up the pertinent consults, asap.
I am guessing she may benefit from both neurological and psych consults.

As for her suicidal feelings, as mentioned above: maybe reach out to guidance counselor if/while waiting on a referral to a mental health professional. She can also check on crisis services in your area. There are also hotlines available.

You may also benefit from support.