Decided to stop breastfeeding and I’m sad

Feeling lightheaded non stop for 2 months almost 3 and I’m on BP medication and I’m eating healthier and drinking water and they did a ct to check my brain and blood work to check if I’m anemic or if my thyroid was out of wack and they also did a ekg and blood work to check my heart and nothing! I get episodes of almost fainting every single day like I haven’t felt normal in a while and I’m so frustrated to think maybe it’s the breastfeeding and I have to decided to stop. But what will break my heart is if I stop and it still continues.