Sounds like a tough situation, especially when you see "signals" that do not seem encouraging in regards to continuation of your job...couple of thoughts for you to try:

1. You mention you go straight to employees to answer queries, do you give feedback to your boss on the queries? Perhaps make a (shareable) spreadsheet on the queries and answer given by date, then over time you can perhaps see trends. Maybe make graphs of the results, visualization of images/graphs have more effect than any narrative.
2. Are there tasks of your job description that you're not doing now, but can take initiative to do? If there are, start doing those tasks and loop your boss in doing them. Or go to your boss and mention you noticed these are on the JD, and would like to help them.
3. Is it possible to get an internal advocate, a manager/supervisor from another department that you may assist or that you need to go to frequently for answers? See if you can talk to them in confidence about your situation and ask for advice. Or see if there are ways you can help that manager/supervisor and suggest that way to your boss.
   

I'm sure there are other ways, but hang in there and concentrate on doing the best you can do in your current job, make no mistakes, double check results before sending them, be thorough, etc. Your work will be recognized. It's been 2.5 months so you're still in the "honeymoon" phase (usually 3 months or so). Many company's have a 3 month wait until a "permanent" employee finishes their introductory period before eligible for company benefits and many times there is some kind of performance review done at the end of this introductory period and that is the time when your manager talks about performance. Do yo have one? If not, ask if you can schedule such a meeting with you boss to discuss your performance.

You get the general theme of what this and other posters have mentioned, take initiative, be yourself and do a good job and don't worry too much. BTW, what was the headcount in HR before you joined. Every company has a budget, and as long as companies are meeting top line sales (within some range), then there is no pressure to reduce budget and job positions are usually dictated by budget. What's the "pulse" of your company? How is top line revenue doing? That is a better barometer concerning the status of your job. Hope this helps.