women with epilepsy

Hey all! I take Lamictal 300mg a day. I had the Mirena for 7 years and did fine, then once I had it taken out I got pregnant shortly after that and just had a healthy baby boy #3. My doctor says that it is my only option because it gives off only a very low dose of hormones and it did well before. Well I've been reading all different things online that says it lowers Lamictal levels. I am praying that my medicine must be working right and it's okay to use again. Opinions on what others may think?! Any advice is great! Also my last seizure 10 years ago was caused from the depo provera birth control shot. Thanks for any advice as my appointment is coming soon!