To see if you're really plagued by a string of bad luck, you'd have to get a reading:http://www.readersandrootworkers.org/in ... ootworkers
That said, we all go through low/rough times. A lot of the time they are cycles in life, periods of learning and development rather than plain bad luck. You're not 100% well at the moment, you're at school and struggling, so it is hard to keep your perspectives clear and grounded. Things will look up after a while. In the meantime, you might want to look at these products.
Get a 13 herb bath, an Uncrossing bath, mix the two plus a dab of Chinese Wash. This should clear away any negativity that's been built up around you (external and self-inflicted) and opens road to better opportunities. Do this for three days. Wash your flat/room with Chinese Wash as well.
A Blessing bath and follow up with a Blessing vigil light. Pray to God that He will give you his blessing, protection and guidance in what you do.
A Crown of Success spell kit, for improved performance at school and opportunities for getting more paid work.