I Have Been Having Lots Of Issues. I’m 25 Noticed

I have been having lots of issues. I’m 25 noticed I was getting sick a lot since the start of last year (colds), which disappeared some. End of July I began getting dizzy/lightheaded spells. They came and went with no real connection to anything. End of September I had Tachycardia. Only thing we could find was low vitamin D. Event monitor only showed the tachy heart rate and some premature beats. Palpitations have calmed but the dizzy spells continue. I get very fatigued some days from it all. Some days are worse than others with dizziness. Also get headaches a lot. Always been healthy. Started new job this summer and moved. But I’ve lived through stress a lot.