Hey there @Private_User 
First of all, a very warm welcome to HS! I hope you get some good use out of the forum.
Seasonal Depression seems like a real nightmare to go through. I know that I do struggle most in the colder months. I have to say, that it takes a lot of courage to come to an open forum like this and seek advice, so for that you should be proud of yourself. The first thing you must realise is that you have valid feelings, and that you aren’t alone.
There can be no doubt, that Seasonal Depression can take a toll on your emotional well-being. However, it’s commendable that you’re actively seeking out coping mechanisms . Self-care is the most important way to cope. Make sure you are engaging in things you enjoy.
You mentioned about having intense anxiety and negative emotions. A good starting point would be to try and figure out what triggers these. Journaling can help with this a lot, so you can see where patterns lie. This is the first step in finding coping mechanisms tailored to your needs.
It goes without saying that reaching out for professional support would be ideal. Family can help in some way too. It’s important that you have your own support system to navigate through these challenges. A professional will be able to give you guidance based on your own situation.
Positive guilt is real. Understanding the way your mind reacts when positive things happen is important. Again, a professional will be able to help you explore this and help you reframe these emotions. Once you address the underlying guilt, you will be open to a positive mindset.
Incorporating gratitude into your life more open is important. Take time out of each day, to appreciate the big, small and tiny wins. Try to see the positive in a negative situation and avoid thinking up the worst case scenario. Doing this won’t rid the challenges you face, but you will become more optimistic.
Finally, progress is gradual my friend. Asking for help is not a weakness. Celebrate the small victories and be patient with yourself. You’ve already reached out here, which is protective. I really do commend you. This issue is temporary, and it won’t last.
You deserve to experience joy and fulfillment, and I believe that with time and effort, you can find effective ways to cope with the challenges you’re facing 