Vitamin deficiency

I really think I am sort of malnourished. I have been breastfeeding my son for 11 months and I don’t eat the best diet. I went through a 2 week phase where I just couldn’t eat. I would eat maybe 1 meal a day. I had personal issues going on which lowered my appetite drastically. I am not bulimic or anorexic. I don’t binge and purge. I have no eating disorders that I know of. I am eating more now, but I don’t eat a well rounded diet. I don’t remember to take prenatals everyday either. My symptoms are muscle weakness and fatigue, heart palpitations, I have more than 10 random huge bruises on my legs at all times. I don’t remember getting them either. I just feel like I am very malnourished. I don’t have energy to keep up with my son or do anything else. I have no motivation either. I am weaning him from the breast because of this. I have also lost 13lbs extra. My BMI is still at a normal range not that it matters too much. But I was a 22.5 and now I’m at 20.0. I am wondering how do I go about asking for my blood to be drawn to figure this out? I don’t want to sound crazy. I just feel so terrible lately.