Hi there - so, you say you have had a tumor on your breast for 1.5 years. That is concerning, and I think the best thing for you to do would be to see a doctor for examination and possibly biopsy of the lump in your breast. If it is breast cancer, and it is not treated, it has the potential to metastasize (spread) to your brain and cause serious problems.
However, you might find that the lump is benign, in which case the symptoms you are experiencing are a totally separate issue. You might have vertigo, or have experienced a micro-stroke, or have blood sugar regulation problems.
The possibilities I mentioned are just a few, and it may be none of those. The first step is to see a doctor for proper examination of your breast lump, and you should do that as soon as possible.