Hi Caridad -- Who is telling you there's a higher bid? If this is an REO (the bank already owns it) and if this bank has multiple offers, the standard operating procedure for the bank is to send back instructions to all bidders that there are several people interested in purchasing this property. They will instruct all of the agents to communicate with their buyers, giving a set time frame for any adjustments to be made to their offers that will reflect their "highest and best " price, terms, etc. If you really don't want to lose this property, you would increase your bid--after obtaining a new market analysis from your agent as to what the current market value is.
Only you know what this property is worth to you. If you feel that your current bid is as high as you can afford, or if you feel it's truly what this property is worth, then don't be swayed by any pressure to change your offer. Of course, if there truly is another bid that is from a qualified buyer, with reasonable terms and a higher price than yours, then you['ll likely lose this "bidding war". I'm a big believer (and it's been proven to be true countless times) that you'll get the house that is right for you. Just keep your head about you, don't get caught up in the emotions of the moment, and have a professional you can trust help you with the process.
Best of luck--
Coldwell Banker Residential Real Estate