I'm so so embarrassed about this and have obviously name changed.
I seem to have the world's most persistent case of threadworms and I don't know what else to try. I can't bring myself to see the Gp - I'm in my 50's and feel so ashamed :(. I've followed all online advice and have taken 6 ovex tablets over the course of the last 3 or 4 months - which is how long I've had them for. 
I shower twice daily. I change my underwear twice daily. I wash towels/bedding/nightwear at least twice a week. I wash my hand thoroughly after using the toilet. I wipe the toilet and flush button after each use. I don't share towels. I'm the only person who uses my en suite.
I have no idea where I can have picked them up from. My youngest dc is 15, I don't work with children and I've no partner.
Please can anyone suggest anything other than the Gp? Could it be something other than threadworm? It's getting me seriously down :(. Very grateful for any suggestions.