Awkward situation with mom

Well, last weekend we had relatives (uncle, aunt, cousins) staying over at our house and my mom slept on the couch in my room because the bedroom where she usually sleeps in was occupied. I didn't mind it because we did this before. Anyways, I woke up in the middle of the night and my mom was awake and on my computer. I didn't want to bother her and tried to fall asleep, but then I heard heavy breathing and scratching noises. I realized that she was looking at porn and masturbating! After she finished, she went back to sleep. I couldn't sleep anymore because I felt so embarassed.
Next day I checked my browser's history and found out she was searching for 'Hot Asian Sex'! I didn't mention anything to her though and she still doesn't know.
Is it normal to feel so embarassed about this?