Towards the end of my period i often see 2cm long of maybe be cells / bits? they thin and be a deep red or kind of white covered in blood. normal?

Likely normal. What you described could be congealed endometrial lining mixed with altered blood and mucus. and would be normal. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV and Covid vaccines. Wish you good health!