Green Smoothie Heartburn & other issues?!

Hi guys. My name is Kel, I'm a n00b here. I've started making an attempt to incorporate more raw/whole foods into my diet. I've been eating "well" for about two years and exercise regularly. Over the past two years, I've dropped about 40lbs. I thought that green smoothies would be a good way to get some more greens, but it seems they hate my body :(

I've been having them for breakfast for about two weeks (I took a few breaks for a day or two) and ever since I've had digestion issues. First off, I've had issues with constipation (sorry for the TMI!) which kind of shocked me because I thought it would do the opposite. I've increased my water intake (from at least 64oz a day to 96) but it doesn't seem to help. All the research I've done basically tells me to eat more leafy greens, so I feel I'm at a loss here. I also have found that the smoothies give me horrendous heartburn!

I thought maybe this was a fruit/almond milk issue, so I tried cutting those and simplifying my smoothies, but it doesn't seem to make it any better. I've done some research & heard that perhaps I had low stomach acid, so I tried the ACV trick and it just made everything worse!

I thought green smoothies were supposed to be healthy and make me feel awesome. I do feel like I have more energy (which I love!) but the side effects are bumming me out! Has anyone had any similar experience? Will this pass? Any ideas?

I should also mention my boyfriend has been drinking the green smoothies as well but he is fine and loving them!