Hi there.. I can understand your concern..but 5inches is normal and not small penis..many males feel they have small penis when actually they wil have normal size. Reasons for small penis could be genetic or hormonal imbalance(reduced testosterone).I don't think any herbs or pills are there that can increase your penis size or girth. Just have confidence and since you have had intercourse once, you would know that your penis is normal size.. Consult sexologist once if you still feel it's small.