are my issues caused by fibroids?

It should be the fibroid i say. Fibroids causes heavy bleeding depending on the location. There are also other causes of heavy bleeding. But research more on fibroids so you will have better understanding or knowledge about it.

It might be the fibroid, but it might not. You don't say whether the dizziness and nausea occurs around your period, but if it does and you have a very heavy flow, you could be low on iron, or be suffering from low blood pressure. Perhaps your Dr tested for that? Fibroids don't always cause heavy periods, some do not cause symptoms at all. I had a large fibroid and many smaller ones, and at first diagnosis I had no idea I even had them. Mine started to press on my bladder and was taking up too much space basically, which is why I had it removed.Try not to worry too much about the fibroid, they are very common and don't always cause problems. However, if the feelings of being unwell continue I would go back to your GP try to get to the bottom of that. Perhaps keep a diary of when you experience dizziness and nausea, and be sure to drink plenty of fluids and rest around your period.

May clearly be anemia.  Simple blood test, ask your doc for it asap!

Dizziness sounds very much like anaemia which can be caused by fibroids or heavy periods and your Doctor needs arrange a blood test to check. You may then be given iron tablets and advice on diet by your Doctor to help. I used to suffer dizziness from fibroids and had to change my diet and take iron supplements. Also is your fibroids 5 inches or 5cm as if its 5 inches then thats is considered a large fibroid and will need to be dealt with as fibroids do get bigger over time.