Bruises on legs without reason

Hi guys.

Long story short, I had to be on my feet for 12hours straight and walked 10 miles at once.

I had sore muscles in my legs the whole day and the next day I get random bruises on my legs. Is this because I over worked my legs? Or I should go to the doctor?

I'm a very lazy person so I never work out in my life and this felt like an intense workout my muscles hurt so bad...

The next day I had sex with my bf and I was on top so my legs got involved again and hurt again and new bruises pop up.

Should I get worried???? 😥