Overwhelmed by touch, sound, smell, thoughts (SPD?)

Hi,

I came here because I am confused if I have SPD. I hope some of you can help me.

I always thought that everyones thoughts are as loud as mine are. It's like they're overlapping and sometimes I can't even finish the sentence I started because I thought about to much other stuff in that time so I can't remember what I was talking about. Friends sometimes tell me I start a sentence and then just stop and stare into space because I forgot what I was talking about or even that I talked to begin with.
Everything feels really loud, like colors and letters and movements feel loud. I can't explain it but it's really overwhelming. This feeling of...loudness is nothing I can put into words.

I have a hard time focussing. Not just in my head, but literally, with my eyes. I realized that when I was lying on the grass last summer and I wanted to focus on a bug - I couldn't manage that and I ended up getting a headache.
I know that sounds ridiculous but I thought for some time that I'm not fit for driving a car because I was convinced that my body was producing alcohol on it's own because everything's always so fast and blurry and unreal. (I know that's not possible but I had no other explanation)

I don't like smells and I get nauseous whenever I smell a strong smell like food or perfume.

Sometimes I physically feel it when people are too close to me. I feel like they're invading my personal space even tho they're like, three metres away. It feels like my nerves are out in the open and everyone is touching them.
I also don't like it when other people indicate physical contact. I have to be the one to touch the other person.

I get rapid mood swings because of this. Like a really small noise or a voice or a person touching me can send my mood into aggression. I feel really bad for that because my friends and family have nothing to do with the way I feel but I can't help the overwhelming aggression rising up sometimes. Sometimes I also feel like crying.

It's not always this bad, I can go days or even weeks without thinking "this is overwhelming". It's always there but it's not always as strong as it is right now.
I get really exhausted when this happens.

But I'm not sure if that's really SDP. Can a doctor diagnose that? I'm just so unsure.

I hope you can understand what I'm talking about. English is not my first language and I can't really concentrate right now.