Hello. i'm taking fluoxetine(motivest) 10 mg papertab/day for my anxiety and 25 mg/night diphenhydramine(benadryl) to treat my insomnia. can i also take valium diazepam 2.5 mg only when my anxiety is attacking? like when only needed?

It should not a big deal for those combination but I would suggest a higher dose of fluoxetine if you have breakthrough attack with that low dose of fluoxetine. Furthermore, you should not use routine benadryl for insomnia. To combat insomnia at your age, the best approach will be practicing sleep hygiene and deep breathing technique if you can't maintain your sleep. Take care.