Welcome to the forums emily!
It seems as if your guy is demonstrating serious mood swings. The best way to find out what is happening with him is to ask him to discuss the situation. You need to know what is wrong before you can even try to fix it. If he is being unfaithful, then you need to ask yourself if that is something you can tolerate in your relationship? The best way to find out for sure if you are pregnant is to take a test. As for financial gain, try to do the best you can to secure a permanent average paying job.
Best wishes,