WAFFLES ~ I'm so sorry about what you are going through; that in itself is extremely stressful and a lot of what you're feeling will stem from that. You are actually grieving the relationship, etc. Now, you are NOT stupid or anything else. Like someone else said -- you are just a human being, who has had a huge hurt dumped on them.
When those negative thoughts come, counteract them with things like -- "NO, I will not allow you to take my happiness and joy away from me. NO, you will not steel my life from me. NO, you will not steel my health from me. NO, you will not steel my success from me!" And so on ...
Most of that 8 lbs is water-weight and probably from some salt in the pizza; just keep going and that will come back off in no time. Yes, continue to come here often -- the people here are caring and so very supportive. They know how you feel becuz they've been through many stress issues themselves. Remember to be kind to yourself each and every day ...