Fear of negative thoughts, low blood pressure...help please

I have a fear of negative thoughts that they will happen if i think them, ever since i had a small accident the day after i was joking about hitting my car, now im obsessed of not thinking negatively i keep knocking on wood and doing superstitious things, i also have low blood pressure, when the pressure drops i feel nausea and lightheaded and it makes me think il get unconscious but i never do, it happens throughout the day, coffe helps a bit, im also very sleepy, my eyes feel tired and i wanna close them,i also got anxiety before i drive sometimes i would take the bus, when i start driving it gets less but i still feel it, i took calc phos and calc fluo combination last few days and i got the poput veins on my legs reduced, i sometimes notice a black floating thing following my vision i notice it when i look at white wall or baclground im tall about 195cm and fat about 134kg, my stool is yellow to dark yellow and i go frequently in the bathroom these last few days, i also had hemmorhoids after diareahh but that passed , i have have hudge stretch marks on my lower back like a tiger claw scratch, my blood pressure gets more frequent when im hungry or havent eaten, i tend to be very pozitive, im optimist, im very very honest and truthfull, i love to travel to ocheans islands and around the world but i dont do it because i get lazy at the thought of trip because its too much work, i eat too much sugar i crave it especially chocolate stuff, i love meat, im a programmer but not ver good at math, i tend to think very logically, im very curious and have a lot of knowledge about lot of subjects im intrigued by pyramids aincent stuff i wanna know the truth and that kind of stuff. I tend to crave sugar more when i lose at a game or im bored or i don't know if im hungry, im also forgetfull and its kinda scaring me, i forget stuff i did few seconds ago, this started happening this year i think im 20 y old. Thanks for taking the time to read this, if you can help me please do. If i remember more stuff i will tell you.