We have some things in common, I see. I also have a son who's 14 months. I'm jealous of you though as I wish I could get him to eat more during the day. He loves nursing. I also am from a line of pro breasfeeding in my family. I did plan on doing the 2 year thing with all 3 of my kids, but it just didn't work out like that.
In general, its not safe to do any type of cleanse while nursing. The reason being is that while cleansing, you're releasing YEARS of stored toxins (doesn't matter that you're 26, I'm 28). We've done alot of damage to our bodies over our short years here. You definitely do not want to expose your baby to them. Imagine if your baby is effected by gassy veggies you ingest, then imagine if you start detoxing and all those chemicals come out of their hiding places in your body. Many people will start breaking out with rashes or headaches while detoxing and thats for people not nursing. Think of whatever's causing that reaction in your breastmilk and in your baby's body. Not a good thought.
I understand that you feel you want to detox. I too have that strong desire, or I wouldn't be on this forum. I've had a LONG battle with candida and other stuff (maybe candida is the root cause) and have a hard time trying to do that diet or try any cleansing if I'm pregnant or nursing. So for me, I know that I need to do this for my health and thats a top priority for me. Not that I'm trying to be selfish, but this is something very important for me. Also, I don't want to end up pregnant again and have to put off for more years to see if my health can truly benefit from cleansing. I have a 6 and 5 year old, both of which have been nursed for 12 and 15 months respectively and they have excellent immunity. But then again, they're homeschooled. But even when they were in school, they didn't seem to be as sick as often as the other ones. Its not just breastfeeding alone with the immunity. They need a good diet too.
Another point, when you do wean, do so gradually. I had a terrible experience with my daughter at 15 months. I weaned her in a week's time and had terrible Depression and anxiety attacks as a result. It lasted for months. The quick weaning sent my hormones crazy. At that time, I also was in a rush to take some medication that wasn't compatible with BF. I later regretted it alot as I wanted to keep nursing her. But now, I really want to wean him completely and try the Colonix many are raving about, but just weaning him from night nursing is turning out to be a nightmare. I must do it though as he's having surgery next week so I didn't want to shock him. I didn't have so much trouble with his sisters. What's good for the goose might not be good for the gander in this case.