I put the toilet seat up from the front using my hands at my work (office) toilet & got distracted and didnt wash my hands and then ended up biting my nails and putting my fingers in my mouth. how likely am i to get threadworms/pin worms from this?

You are not at risk of worm infestation from what you described. 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 vaccine. Wish you good health!

Unless there is breakout of parasitosis (1 or more colleagues having worms) in your office, you are not likely to get parasites. However, hands hygiene remains critical as a multitude of other bacteria and viruses, including Hep A remain possible.

You won't contact any diseases unless you had open sores on your hands or fingers. You have a bad habit of biting nails and putting fingers in mouth which could put you at risk in future depending what you touch. Also practice good oral and body hygiene.