my mac mail will not search mail anymore and doesn't load attachments anymore

Does anyone know why this would be happening?

My mac mail will not search mail anymore and doesn't load attachments most of the time. When I enter some text in the search box no results come up and I know there are messages that contain the phrase that I've entered.

Also about 3 weeks ago attachments only get loaded about 1/4 of the way - if that. So I have to log onto my web based mail program from the host and retrieve attachements or check the messgae with my iphone.

Please - does anyone know how to fix this?